Final

An electron follows a circular path (radius = 15 cm) in a uniform magnetic field (magnitude = 3.0 G). What is the period of this motion? Question options: 1) 0.12 ms 2) 1.2 ms 3) 0.18 ms 4) 1.8 ms 5) 1.8 ms

1) 0.12 ms

A 60-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with . The power factor, is a.! -1.00. b.! -0.936. c.! +0.943. d.! +0.936. e.! +1.00.

d.! +0.936.

An LC circuit is to have resonant oscillations at 5.0 MHz. Find the value of a capacitor which will work with a 1.0-mH inductor. a.! 2 mF b.! 1 µF c.! 0.02 µF d.! 1 pF e.! 40 pF

d.! 1 pF

A 60-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with . The impedance is a.! 3.77 Ω. b.! 9.26 Ω. c.! 10.0 Ω. d.! 10.7 Ω. e.! 13.8 Ω.

d.! 10.7 Ω.

A 230 000 V-rms powerline carries an average power PAV = 250 MW a distance of 200 km. If the total resistance of the cables is 10 ohms, what is the resistive power loss? a.! 1.0 MW b.! 2.5 MW c.! 5.4 MW d.! 12 MW e.! 10 kW

d.! 12 MW

In the subshell of the Li2+ ion with orbital quantum number , the allowed values of the magnetic quantum number are Question options: 1) - to 2) -( + 1) to ( + l) 3) -( + 2) to ( + 2) 4) -( + 3) to ( + 3) 5) 0 to n - 1

1) - to

Approximately how fast is an ion of helium moving if it is in a plasma with a temperature of 108 K? m(He) = 4.002603 u and u = 1.66 ´ 10-27 kg. Question options: 1) 106 m/s 2) 104 m/s 3) 102 m/s 4) 10 m/s 5) 1 m/s

1) 106 m/s

Characteristic x-rays can be produced by bombarding targets with electrons. These x-rays occur when Question options: 1) electrons from higher shells fill the vacant lower shell 2) electrons fill the vacant valence shell 3) photons are emitted with energies on the order of 103 eV 4) photons are emitted with wavelengths on the order of 103 nm

1) electrons from higher shells fill the vacant lower shell

A neutron is characterized by the term "thermal neutron" when Question options: 1) its energy is of the order kT, where T is on the order of 0°C. 2) its energy is of the order kT, where T is on the order of 0 K. 3) its energy is of the order kT, where T is on the order of 273 K. 4) its energy is of the order kT, where T is on the order of 100°C. 5) its energy is of the order kT, where T is on the order of 0°R.

1) its energy is of the order kT, where T is on the order of 0°C.

The Pauli Exclusion Principle states Question options: 1) no two electrons in the same atom can have the same set of quantum numbers. 2) there is an inherent uncertainty in the position and momentum of a particle. 3) when an atom has orbitals of equal energy, the maximum number of electrons will have unpaired spins. 4) when an atom has orbitals of equal energy, the maximum number of electrons will be paired spins. 5) no two atoms can have the same set of quantum numbers.

1) no two electrons in the same atom can have the same set of quantum numbers.

One roentgen is defined as Question options: 1) the amount of ionizing radiation that will produce 1/3 ´ 10-9 C of electric charge in 1 cm3 of air under standard conditions. 2) the amount of radiation that deposits 10-2 J of energy into 1 kg of absorbing material. 3) the amount of radiation needed for ionization of an atom. 4) the amount of radiation needed for dissociation of a molecule. 5) the amount of radiation that deposits 1 erg of energy in 1 g of air.

1) the amount of ionizing radiation that will produce 1/3 ´ 10-9 C of electric charge in 1 cm3 of air under standard conditions.

One rad is Question options: 1) the amount of radiation that deposits 10-2 J of energy into 1 kg of absorbing material. 2) the amount of ionizing radiation that will produce 1/3 ´ 10-9 C of electric charge in 1 cm3 of air under standard conditions. 3) the amount of radiation needed for ionization of an atom. 4) the amount of radiation needed for dissociation of a molecule. 5) the amount of radiation that deposits one erg of energy in 1g of material.

1) the amount of radiation that deposits 10-2 J of energy into 1 kg of absorbing material.

A principal mechanism for energy loss during nuclear fusion is bremsstrahlung. This loss is associated with Question options: 1) x-rays emitted due to electron-ion collisions. 2) radiation losses due to T4 losses. 3) conduction losses associated with DT. 4) convection losses associated with DT. 5) neutron collisions with atoms of moderator.

1) x-rays emitted due to electron-ion collisions.

What energy is needed (in MeV) so two deuterium atoms moving together will reach the necessary 10-14 m for fusion? Question options: 1) 0.511 2) 0.14 3) 2.5 4) 4.3 5) 1.0

2) 0.14

An electron in a hydrogen atom makes a transition from the n = 4 to the n = 3 energy state. Determine the energy (in eV) of the emitted photon. Question options: 1) 0.54 2) 0.66 3) 0.85 4) 1.51 5) 10.2

2) 0.66

What is the average kinetic energy (in keV) of an ion that has a temperature of 108 K? Question options: 1) 8 2) 13 3) 4 4) 16 5) 21

2) 13

The ground state configuration of chlorine (Z = 17) is Question options: 1) 1s2 2s2 2p5 3s2 3p6 2) 1s2 2s2 2p6 3s2 3p5 3) 1s2 2s2 2p6 3s2 3p4 3d1 4) 1s2 2s2 2p6 3s2 3p5 4s1 5) 1s2 2s2 2p6 3s1 3p7

2) 1s2 2s2 2p6 3s2 3p5

How fast is the electron moving in the first Bohr orbit? Question options: 1) 3.3 ´ 106 m/s 2) 2.2 ´ 106 m/s 3) 4.4 ´ 106 m/s 4) 5.5 ´ 106 m/s 5) 5.5 ´ 1015 m/s

2) 2.2 ´ 106 m/s

Find the number of nuclei per unit volume (n = nuclei/cm3) for lead. atomic weight = 202.7 density = 11.5 g/cm3 Avogadro's number = 6.02 ´ 1023 Question options: 1) 2.5 ´ 1022 2) 3.4 ´ 1022 3) 2.9 ´ 1022 4) 2.9 ´ 1023 5) 2.0 ´ 1021

2) 3.4 ´ 1022

The energy needed to remove an electron from the first excited state of a Li2+ ion is Question options: 1) 53 eV 2) 31 eV 3) 92 eV 4) 122 eV 5) 61 eV

2) 31 eV

A headwaiter at a restaurant decides to apply the exclusion principle to the seating of patrons. He will treat tables as sub-shells, and will only seat patrons if the number of the people to be seated adds up to a complete sub-shell. Of the numbers below, the number he would not be willing to seat at one table is Question options: 1) 2. 2) 4. 3) 6. 4) 10. 5) 14.

2) 4.

The energy needed to change a He+ ion in the ground state into a He2+ ion is Question options: 1) 13.6 eV 2) 54.4 eV 3) 112.4 eV 4) 92.9 eV 5) 27.2 eV

2) 54.4 eV

For the following allowed transitions, which photon would have the largest wavelength when an electron "jumps" from one energy level, characterized by the quantum number n, to another? Question options: 1) n = 2 to n = 1 2) n = 3 to n = 2 3) n = 3 to n = 1 4) n = 1 to n = 3 5) n = 4 to n = 1

2) n = 3 to n = 2

The allowed values of for the n = 3 shell in a Li2+ ion are Question options: 1) 1, 2 2) 0, 1 3) 0, 1, 2 4) 0, 1, 2, 3 5) 1, 2, 3

3) 0, 1, 2

In neutron capture by an atomic nucleus, the atomic number changes by Question options: 1) -2. 2) -1. 3) 0. 4) +1. 5) +2.

3) 0.

A hydrogen atom is in its first excited state (n = 2). The linear momentum of the electron is (in kg × m/s) Question options: 1) 3 ´ 10-24 2) 2 ´ 10-24 3) 1 ´ 10-24 4) 4 ´ 10-24 5) 3 ´ 10-15

3) 1 ´ 10-24

What is the difference in frequency for spectral lines emitted by hydrogen for transitions from the n = 16 level to the n = 2 level and transitions from the n = 15 level to the n = 2 level? (RH = 1.097 ´ 10-7 m-1.) Question options: 1) 5.65 ´ 10-13 Hz 2) 31 Hz 3) 1.77 ´ 1012 Hz 4) 2.55 ´ 1016 Hz 5) 1.02 ´ 1017 Hz

3) 1.77 ´ 1012 Hz

Background radiation from cosmic rays and radoactive nuclei in our surroundings is about 0.13 rem/year. Suppose we assume this all comes from cosmic rays which have an RBE factor of 1.0. The RBE factor for the most dangerous types of radiation is 20. How many rads of the most dangerous radiation could a 100-year-old person have been exposed to in her lifetime without having gone over the recommended limit of 0.5 rem/year? Question options: 1) 0.37 2) 0.50 3) 1.85 4) 13 5) 37

3) 1.85

In a shell of the hydrogen atom with n = 3, the permitted values of the orbital magnetic quantum number are Question options: 1) -1, 0, 1 2) 2, 1, 0 3) 2, 1, 0, -1, -2 4) 0 5) 3, 2, 1, 0, -1, -2, -3

3) 2, 1, 0, -1, -2

Of the following states of the hydrogen atom, 1s, 2p, 3d, 4f, 4s, which answer lists all the states that are not spherically symmetrical? Question options: 1) 1s, 4s 2) 3d, 4f 3) 2p, 3d, 4f 4) 2p, 3d, 4s, 4f 5) 1s, 4s, 4f

3) 2p, 3d, 4f

A beam of 1-MeV gamma rays incident on a piece of 1/2-cm thick lead is reduced by 50% of its initial value. How thick must the lead be to reduce the beam to 1% of its initial value? Question options: 1) 1.1 cm 2) 2.2 cm 3) 3.3 cm 4) 4.4 cm 5) 8.4 cm

3) 3.3 cm

A Li2+ ion undergoes a transition from the n = 4 to the n = 3 state. The energy of the emitted photon is Question options: 1) 4.5 eV 2) 10.2 eV 3) 5.95 eV 4) 2.6 eV 5) 0.66 eV

3) 5.95 eV

The number of states in the He+ ion corresponding to the principle quantum number n = 5 are Question options: 1) 18 2) 25 3) 50 4) 9 5) 11

3) 50

Radioactive technetium, a gamma emitter, is taken up by the heart muscle in a medical test. The detector for the radiation emitted from the heart could be a Question options: 1) Tokamak. 2) quarter-wavelength antenna. 3) Geiger counter. 4) photoelectric tube. 5) diffraction grating.

3) Geiger counter

An energy of 13.6 eV is needed to ionize an electron from the ground state of a hydrogen atom. What wavelength is needed if a photon accomplishes this task? Question options: 1) 60 nm 2) 80 nm 3) 70 nm 4) 90 nm 5) 40 nm

4) 90 nm

When electrons fill a subshell in which the orbitals have equal energy, the order in which the orbitals are filled is such that Question options: 1) a minimum number of electrons has unpaired spins. 2) a minimum number of electrons has intrinsic angular momentum. 3) a maximum number of electrons has unpaired spins. 4) a maximum number of electrons first fills the next energy level. 5) the maximum number of electrons has the same set of quantum numbers.

3) a maximum number of electrons has unpaired spins.

Forbidden transitions and selection rules suggest that Question options: 1) a photon has linear momentum. 2) a photon has energy. 3) a photon has angular momentum. 4) a photon has parity. 5) a photon has mass.

3) a photon has angular momentum.

Suppose Bohr had chosen the potential energy of the electron in the hydrogen atom to be V = 0 when the electron is in the orbit with n = 1. He could do this by Question options: 1) choosing n = 1 for the orbit where the kinetic energy of the electron is zero. 2) adding a constant 13.6 eV to the potential energy for all values of n. 3) adding a constant 27.2 eV to the potential energy for all values of n. 4) subtracting a constant 13.6 eV from the potential energy for all values of n. 5) subtracting a constant 27.2 eV from the potential energy for all values of n.

3) adding a constant 27.2 eV to the potential energy for all values of n.

In 1921, Stern and Gerlach performed an experiment that first demonstrated Question options: 1) orbital angular momentum quantization 2) energy quantization 3) space quantization 4) magnetic orbital quantization 5) that particles behave like waves

3) space quantization

A self-sustained chain reaction occurs when the reproduction constant, K, is equal to Question options: 1) 3.0 2) 2.0 3) 2.5 4) 1.0 5) 0.5

4) 1.0

What wavelength (in mm) is associated with the Paschen series for n = 4? (RH = 1.097 ´ 107 m-1) Question options: 1) 320 2) 530 3) 2.7 4) 1.9 5) 0.5

4) 1.9

An electron in a hydrogen atom makes a transition from the n = 3 to the n = 1 energy state. Determine the wavelength of the emitted photon (in nm). Question options: 1) 1006 2) 209 3) 306 4) 103 5) 821

4) 103

What angle does the orbital angular momentum make with the z axis of a hydrogen atom in the state n = 3, = 2, = -1? Question options: 1) -66° 2) 66° 3) 24° 4) 114° 5) 73°

4) 114°

Light is emitted by hydrogen atoms in the visible range for a hydrogen atom. Its wavelength is 656 nm. What value of n is associated with the light? (RH = 1.097 ´ 107 m-1) Question options: 1) 5 2) 2 3) 4 4) 3 5) 6

4) 3

An electron is moving at a speed of 2.1 ´ 106 m/s in the first Bohr orbit. Determine its de Broglie wavelength. Question options: 1) 0.3 ´ 10-10 m 2) 1.7 ´ 10-10 m 3) 0.5 ´ 10-10 m 4) 3.5 ´ 10-10 m 5) 1.5 ´ 10-10 m

4) 3.5 ´ 10-10 m

Of the following states, 5s, 3p, 4f, 5p, 4g, 3d, and 2p, the one which is NOT allowed is Question options: 1) 3p 2) 4f 3) 3d 4) 4g 5) 2p

4) 4g

What is the difference in wavelength for spectral lines emitted by hydrogen for transitions from the n = 16 level to the n = 2 level and transitions from the n = 15 level to the n = 2 level? (RH = 1.097 ´ 10-7 m-1.) Question options: 1) 1.0 ´ 10-10 m 2) 2.0 ´ 10-10 m 3) 4.1 ´ 10-10 m 4) 8.1 ´ 10-10 m 5) 1.6 ´ 10-9 m

4) 8.1 ´ 10-10 m

Which of the following statements is true? Question options: 1) L can never be perpendicular to B. 2) L can be aligned parallel to B. 3) L must be perpendicular to B. 4) L can never be aligned parallel to B.

4) L can never be aligned parallel to B.

In a completely filled atomic shell, Question options: 1) the intrinsic spin of the electrons does not produce a resultant magnetic moment. 2) the orbital motion of the electrons does not produce a resultant magnetic moment. 3) the electrons do not contribute to paramagnetic or ferromagnetic effects. 4) all of the above are correct. 5) none of the above are correct.

4) all of the above are correct.

Which of the following is not a radiation detector? Question options: 1) cloud chamber 2) Geiger counter 3) scintillation counter 4) neutron activation 5) spark chamber

4) neutron activation

The nuclear scattering cross-sections of neutrons depend most strongly on the neutron's Question options: 1) mass 2) area 3) volume 4) speed 5) charge

4) speed

Rubidium (Z = 37) and potassium (Z = 19) are similar to sodium in that they have ____ electron(s) in the outermost shell. Question options: 1) five p 2) three p 3) two s 4) one d 5) one s

5) one s

A nuclear reactor is said to be critical when the average number of neutrons from each fission event that cause(s) another fission event is Question options: 1) <1. 2) 1. 3) >1. 4) any of the above. 5) only (b) or (c) above.

5) only (b) or (c) above.

Capacitive reactance XC is given by a.! 1/ωC b.! ωC c.! ω/C d.! C/ω e.! 1/ω2C

a. 1/ωC

The primary winding of an electric train transformer has 400 turns and the secondary has 50. If the input voltage is 120V(rms) what is the output voltage? a.! 15 V (rms) b.! 30 V (rms) c.! 60 V (rms) d.! 2.4 V (rms) e. 960 V (rms)

a. 15 V (rms)

A series RLC circuit has an impedance of 120Ω and a resistance of 64Ω. What average power is delivered to this circuit when Vrms = 90 volts? a.! 36 W b.! 100 W c.! 192 W d.! 360 W e.! 12 W

a. 36 W

At what frequency will a 12-µF capacitor have a reactance XC = 300Ω? a.! 44 Hz b.! 88 Hz c.! 176 Hz d.! 352 Hz e.! 278 Hz

a. 44 Hz

Two identical silver spheres of mass m and radius r are placed a distance R (sphere 1) and 2R (sphere 2) from the sun respectively. The ratio of the pressure of solar radiation on sphere 2 to that on sphere 1 is a.! 0.25. b.! 0.50. c.! 1.0. d.! 2.0. e.! 4.0.

a.! 0.25.

A solar cell has a light-gathering area of 10 cm2 and produces 0.2 A at 0.8 V (DC) when illuminated with S = 1000 W/m2 sunlight. What is the efficiency of the solar cell? a.! 16% b.! 7% c.! 23% d.! 4% e.! 32%

a.! 16%

Light strikes a diamond (n = 2.42) at an angle of 60° relative to the normal to the surface. What is the angle of refraction? a.! 21° b.! 30° c.! 38° d.! 69° e.! 71°

a.! 21°

Two mirrors are at right angles to one another. If an object is placed near the mirrors, what is the largest number of images that would be seen in the mirrors? a.! 3 b.! 2 c.! 4 d." 5 e.! 6

a.! 3

Find the frequency of X-rays of wavelength 1 Å = 10-10 m. a.! 3 × 1018 Hz b.! 3 × 1010 MHz c.! 6 × 109 Hz d.! 3 × 108 Hz e.! 3 × 1020 Hz

a.! 3 × 1018 Hz

How much electromagnetic energy is contained in each cubic meter near the Earth's surface if the intensity of sunlight under clear skies is 1000 W/m2? a.! 3.3 × 10-6 J b.! 3.3 J c.! 0.003 J d.! 10-4 J e.! 3.0 × 105 J

a.! 3.3 × 10-6 J

Green light has a wavelength of 5.4 × 10-7 m. What is the frequency of this EMwave in air? a.! 5.55 × 1014 Hz b.! 6.00 × 1011 Hz c.! 9.00 × 108 Hz d.! 3.00 × 1010 MHz e.! 1.80 × 1015 Hz

a.! 5.55 × 1014 Hz

Find the force exerted by reflecting sunlight off a reflecting aluminum sheet in space if the area normal to the sunlight is 10 000 m2 and the solar intensity is 1350 W/m2. a.! 0.72 N b.! 0.09 N c.! 9 N d.! 45 N e.! 0.18 N

b.! 0.09 N

A diver shines an underwater searchlight at the surface of a pond (n = 1.33). At what angle (relative to the surface) will the light be totally reflected? a.! 47° b.! 41° c.! 51° d.! 58° e.! 49°

b.! 41°

A fish is 80 cm below the surface of a pond. What is the apparent depth (in cm) when viewed from a position almost directly above the fish? (For water, n = 1.33.) a.! 50 b.! 60 c.! 40 d.! 70 e.! 110

b.! 60

Two mirrors are at right angles to one another. A light ray is incident on the first at an angle of 30° with respect to the normal to the surface. What is the angle of reflection from the second surface? a.! 30° b.! 60° c.! 45° d.! 53° e.! 75°

b.! 60°

At a distance of 10 km from a radio transmitter, the amplitude of the E-field is 0.20 volts/meter. What is the total power emitted by the radio transmitter? a.! 10 kW b.! 67 kW c.! 140 kW d.! 245 kW e.! 21 kW

b.! 67 kW

According to Einstein's theory, the energy of a photon is a.! proportional to its wavelength. b.! proportional to its frequency. c.! constant, since the speed of light is a constant. d.! quantized, since it always appears in bundles of size, 1.6 × 10-19 C. e.! proportional to the square of the frequency.

b.! proportional to its frequency.

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface. The edges of the two mirrors meet at a angle. A light ray that approaches mirror 1 is parallel to mirror 2. The angle of reflection of that ray from mirror 1 is a. 0 b. 30 c. 60 d. 90 e. 120

c. 60

the ratio for sphere 2 is T2. The ratio of T2 to T1 is a.! 0.25. b.! 0.50. c.! 1.0. d.! 2.0. e.! 4.0.

c.! 1.0.

When light is either reflected or refracted, the quantity that does not change in either process is its a.! direction of travel. b.! dispersion. c.! frequency. d.! speed. e.! wavelength.

c.! frequency.

A monochromatic (single frequency, single wavelength) light ray in air (n = 1) enters a glass prism (n = 1.5). In the glass prism a." both the frequency and the wavelength are the same as in air b." the frequency is the same, but the wavelength is greater than in air. c." the frequency is the same, but the wavelength is smaller than in air. d." the wavelength is the same, but the frequency is greater than in air. e." the wavelength is the same, but the frequency is smaller than in air.

c." the frequency is the same, but the wavelength is smaller than in air.

In a parallel RLC circuit, where Ir = Ir,max(sin(wt)) , the current through the capacitor, Ic, is a. Ic = -Ic,max(sin(wt)). b. Ic = Ic,max(sin(wt)). c. Ic = -Ic,max(cos(wt)). d. Ic = Ic,max(cos(wt)). e. Ic = Ic,max(tan(wt)).

d. Ic = Ic,max(cos(wt)).

An aquarium contains a 5-cm layer of water (n = 1.33) floating on top of carbon tetrachloride (n = 1.461). If the angle of incidence into the water from the air is 30°, what is the angle of refraction into the carbon tetrachloride? a.! 58° b.! 69° c.! 37° d.! 20° e.! 75°

d.! 20°

A light ray whose frequency is 6 × 1014 Hz in vacuum is incident on water (n = 1.33). The wavelength of the light after it enters the water is (in nm) a.! 798 b.! 500 c.! 665 d.! 376 e.! 266

d.! 376

What is the maximum radiation pressure exerted by sunlight in space (S = 1350 W/m2) on a flat black surface? a.! 2.25 × 10-5 Pa b.! 0.06 Pa c.! 7 × 10-4 Pa d.! 4.5 × 10-6 Pa e.! 9.0 × 10-6 Pa

d.! 4.5 × 10-6 Pa

A person in a boat sees a fish in the water (n = 1.33), the light rays making an angle of 40° relative to the water's surface. What is the true angle (in degrees) relative to the water's surface of the same rays when beneath the surface? a.! 40 b.! 35 c.! 50 d.! 55 e." 61

d.! 55

The first successful measurement of the speed of light was made by a.! Rene Descartes. b.! Armand Fizeau. c.! Christian Huygens. d.! Ole Roemer. e.! James Maxwell.

d.! Ole Roemer.

At every instant the ratio of the magnitude of the electric to the magnetic field in an electromagnetic wave in vacuum is equal to a.! the speed of radio waves. b.! the speed of light. c.! the speed of gamma rays. d.! all of the above. e.! only (a) and (b) above.

d.! all of the above.

Magnetic fields are produced by a.! constant electric currents. b.! electric currents that vary sinusoidally with time. c.! time-varying electric fields. d.! all of the above. e.! only (a) and (b) above.

d.! all of the above.

You can raise the temperature of an object with a.! microwaves. b.! infrared waves. c.! ultraviolet rays. d.! all of the above. e.! only (a) and (b) above

d.! all of the above.

An open circuit consists of a 12 µF parallel plate capacitor charged to 200 V and a 10 Ohm resistor. At the instant when a switch closes the circuit (with no battery in it) the displacement current between the plates of the capacitor is a. 1.2 µA b. 2.4*10^-4 A c. 2.4 mA d. 10 A e. 20 A

e. 20

The angle between two plane mirrors that meet at one edge is . The change in direction of a ray that strikes the first mirror at a angle of incidence when that ray reflects from the second mirror is a.! 0 b.! 45 c.! 90 d.!. 180 e.!. 270

e. 270

A certain brand of hot dog cooker applies a potential difference (120 V) to opposite ends of the hot dog and cooks by means of the joule heat produced. If 60 kJ is needed to cook each hot dog, what current is needed to cook four hot dogs simultaneously in 3.0 min? 1) 11 A 2) 2.8 A 3) 8.3 A 4) 2.1 A 5) 3.6 A

1) 11 A

A charged particle (m = 5.0 g, q = -70 mC) moves horizontally at a constant speed of 30 km/s in a region where the free fall gravitational acceleration is 9.8 m/s2 downward, the electric field is 700 N/C upward, and the magnetic field is perpendicular to the velocity of the particle. What is the magnitude of the magnetic field in this region? Question options: 1) 47 mT 2) zero 3) 23 mT 4) 35 mT 5) 12 mT

1) 47 mT

A charged particle moves in a region of uniform magnetic field along a helical path (radius = 5.0 cm, pitch = 12 cm, period = 5.0 ms). What is the speed of this particle as it moves along this path? Question options: 1) 67 m/s 2) 26 m/s 3) 63 m/s 4) 24 m/s 5) 87 m/s

1) 67 m/s

When a 20-V emf is placed across two resistors in series, a current of 2.0 A is present in each of the resistors. When the same emf is placed across the same two resistors in parallel, the current through the emf is 10 A. What is the magnitude of the greater of the two resistances? 1) 7.2 W 2) 7.6 W 3) 6.9 W 4) 8.0 W 5) 2.8 W

1) 7.2 W

A straight wire carries a current of 40 A in a uniform magnetic field (magnitude = 80 mT). If the force per unit length on this wire is 2.0 N/m, determine the angle between the wire and the magnetic field. Question options: 1) either 39° or 141° 2) either 25° or 155° 3) either 70° or 110° 4) either 42° or 138° 5) either 65° or 115°

1) either 39° or 141°

A 2.0-m wire carries a current of 15 A directed along the positive x axis in a region where the magnetic field is uniform and given by B = (30i - 40j) mT. What is the resulting magnetic force on the wire? Question options: 1) (+1.2 k) N 2) (-1.2 k) N 3) (-1.5 k) N 4) (+1.5 k) N 5) (+0.90 k) N

2) (-1.2 k) N

A 2.0-C charge moves with a velocity of (2.0i + 4.0j + 6.0k) m/s and experiences a magnetic force of (4.0i - 20j + 12k) N. The x component of the magnetic field is equal to zero. Determine the y component of the magnetic field. Question options: 1) -3.0 T 2) +3.0 T 3) +5.0 T 4) -5.0 T 5) +6.0 T

2) +3.0 T

A physicist claims that she has found a new particle with a mass 200,000 times the mass of the proton (1.67 ´ 10-27 kg) and a charge of 3.20 ´ 10-19 C. If she is correct, such a particle traveling in a circle in a uniform 5.00 T magnetic field at a velocity of 2500 m/s will have a radius of Question options: 1) 0.261 m. 2) 0.522 m. 3) 1.04 m. 4) 3.27 m. 5) 3.13 ´ 1026 m.

2) 0.522 m.

What is the kinetic energy of an electron that passes undeviated through perpendicular electric and magnetic fields if E = 4.0 kV/m and B = 8.0 mT? Question options: 1) 0.65 eV 2) 0.71 eV 3) 0.84 eV 4) 0.54 eV 5) 1.4 eV

2) 0.71 eV

A 2.0-C charge moves with a velocity of (2.0i + 4.0j + 6.0k) m/s and experiences a magnetic force of (4.0i - 20j + 12k) N. The x component of the magnetic field is equal to zero. Determine the z component of the magnetic field. Question options: 1) -3.0 T 2) +3.0 T 3) +5.0 T 4) -5.0 T 5) +6.0 T

3) +5.0 T

How long will it take a charged 80-mF capacitor to lose 20% of its initial energy when it is allowed to discharge through a 45-W resistor? 1) 0.92 ms 2) 0.64 ms 3) 0.40 ms 4) 0.19 ms 5) 0.80 ms

3) 0.40 ms

A segment of wire carries a current of 25 A along the x axis from x = -2.0 m to x = 0 and then along the z axis from z = 0 to z = 3.0m. In this region of space, the magnetic field is equal to 40 mT in the positive z direction. What is the magnitude of the force on this segment of wire? Question options: 1) 1.0 N 2) 5.0 N 3) 2.0 N 4) 3.6 N 5) 3.0 N

3) 2.0 N

An electron has a velocity of 6.0 ´ 106 m/s in the positive x direction at a point where the magnetic field has the components Bx = 3.0 T, By = 1.5 T, and Bz = 2.0 T. What is the magnitude of the acceleration of the electron at this point? Question options: 1) 2.1 ´ 1018 m/s2 2) 1.6 ´ 1018 m/s2 3) 2.6 ´ 1018 m/s2 4) 3.2 ´ 1018 m/s2 5) 3.7 ´ 1018 m/s2

3) 2.6 ´ 1018 m/s2

How many time constants must elapse if an initially charged capacitor is to discharge 55% of its stored energy through a resistor? 1) 0.60 2) 0.46 3) 0.52 4) 0.40 5) 1.1

4) 0.40

What value of B should be used in a velocity selector to separate out 2.0-keV protons if E is fixed at 80 kV/m? Question options: 1) 0.18 T 2) 0.11 T 3) 0.15 T 4) 0.13 T 5) 0.23 T

4) 0.13 T

An unusual lightning strike has a vertical portion with a current of -400 A downwards. The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 mT. In N, the force exerted by the Earth's magnetic field on the 25 m-long current is Question options: 1) 0. 2) 0.012 A, East. 3) 0.012 A, West. 4) 0.30 A, West. 5) 300 A, East.

4) 0.30 A, West.

A velocity selector uses a fixed electric field of magnitude E and the magnetic field is varied to select particles of various energies. If a magnetic field of magnitude B is used to select a particle of a certain energy and mass, what magnitude of magnetic field is needed to select a particle of equal mass but twice the energy? Question options: 1) 0.50 B 2) 1.4 B 3) 2.0 B 4) 0.71 B 5) 1.7 B

4) 0.71 B

An electron moves in a region where the magnetic field is uniform, has a magnitude of 60 mT, and points in the positive x direction. At t = 0 the electron has a velocity that has an x component of 30 km/s, a y component of 40 km/s, and a z component of zero. What is the pitch of the resulting helical path? Question options: 1) 13 mm 2) 32 mm 3) 24 mm 4) 18 mm 5) 3.8 mm

4) 18 mm

What is the magnitude of the magnetic force on a charged particle (Q = 5.0 mC) moving with a speed of 80 km/s in the positive x direction at a point where Bx = 5.0 T, By = -4.0 T, and Bz = 3.0 T? Question options: 1) 2.8 N 2) 1.6 N 3) 1.2 N 4) 2.0 N 5) 0.4 N

4) 2.0 N

If 480 C pass through a 4.0-W resistor in 10 min, what is the potential difference across the resistor? 1) 3.6 V 2) 2.8 V 3) 2.4 V 4) 3.2 V 5) 5.0 V

4) 3.2 V

A segment of wire carries a current of 25 A along the x axis from x = -2.0 m to x = 0 and then along the y axis from y = 0 to y = 3.0 m. In this region of space, the magnetic field is equal to 40 mT in the positive z direction. What is the magnitude of the force on this segment of wire? Question options: 1) 2.0 N 2) 5.0 N 3) 1.0 N 4) 3.6 N 5) 3.0 N

4) 3.6 N

A resistor of unknown resistance and a 15-W resistor are connected across a 20-V emf in such a way that a 2.0 A current is observed in the emf. What is the value of the unknown resistance? 1) 75 W 2) 12 W 3) 7.5 W 4) 30 W 5) 5.0 W

4) 30 W

A particle (m = 3.0 mg, q = 5.0 mC) moves in a uniform magnetic field given by (60j) mT. At t = 0 the velocity of the particle is equal to (30j - 40k) m/s. The subsequent path of the particle is Question options: 1) circular with a 50-cm radius. 2) helical with a 6.3-cm pitch. 3) circular with a period of 31 ms. 4) helical with a 40-cm radius. 5) none of the above

4) helical with a 40-cm radius.

One reason why we know that magnetic fields are not the same as electric fields is because the force exerted on a charge +q Question options: 1) is in opposite directions in electric and magnetic fields. 2) is in the same direction in electric and magnetic fields. 3) is parallel to a magnetic field and perpendicular to an electric field. 4) is parallel to an electric field and perpendicular to a magnetic field. 5) is zero in both if the charge is not moving.

4) is parallel to an electric field and perpendicular to a magnetic field.

In a loop in a closed circuit, the sum of the currents entering a junction equals the sum of the currents leaving a junction because 1) the potential of the nearest battery is the potential at the junction. 2) there are no transformations of energy from one type to another in a circuit loop. 3) capacitors tend to maintain current through them at a constant value. 4) current is used up after it leaves a junction. 5) charge is neither created nor destroyed at a junction.

5) charge is neither created nor destroyed at a junction.

A 60-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 Ω and C = 300mF. The peak current in the circuit is a. 8.24 A. b. 8.84 A. c. 11.0 A. d. 12.4 A e. 23.5 A

a. 8.24 A.

Inductive reactance XL is given by a.! Lω b.! L/ω c.! 1/Lω d.! ω/L e.! ω2L

a. Lω

An electric heater draws an average power of 1100 Watts when plugged into a 110 V-rms outlet. Calculate the resistance of the heater and the rms current. a.! 11Ω, 10 A (rms) b.! 110Ω, 10 A (rms) c.! 10Ω, 11 A (rms) d.! 10Ω, 110 A (rms) e.! 0.09Ω, 11 A (rms)

a.! 11Ω, 10 A (rms)

A 10-µF capacitor is plugged into a 110 V-rms 60-Hz voltage source, with an ammeter in series. What is the rms value of the current through the capacitor? a.! 0.202 A (rms) b.! 0.415 A (rms) c.! 0.626 A (rms) d.! 0.838 A (rms) e.! 0.066 A (rms)

b. 0.415 A (rms)

A current I = 3 sin (400 t) amperes flows in a series RL circuit in which L = 1 mH and R = 100Ω. What is the average power loss? a.! 225 W b.! 450 W c.! 980 W d.! 1.12 kW e.! 900 W

b.! 450 W

If R = 10 ohms, L = 0.1 henry, C = 10 µF, what is the resonant frequency for the parallel RLC-circuit? a.! 1000 Hz b.! 333 Hz c.! 159 Hz d.! 53 Hz e.! 500 Hz

c.! 159 Hz

Whenever the alternating current frequency in a series RLC circuit is halved, a.! the inductive reactance is doubled and the capacitive reactance is halved. b.! the inductive reactance is doubled and the capacitive reactance is doubled. c.! the inductive reactance is halved and the capacitive reactance is halved. d.! the inductive reactance is halved and the capacitive reactance is doubled. e.! the reactance of the circuit remains the same.

d.! the inductive reactance is halved and the capacitive reactance is doubled.

A particle (mass = 2.0 mg, charge = -6.0 mC) moves in the positive direction along the x axis with a velocity of 3.0 km/s. It enters a magnetic field of (2.0i + 3.0j + 4.0k) mT. What is the acceleration of the particle? Question options: 1) (36j - 27k) m/s2 2) (-36j + 27k) m/s2 3) (-24j + 18k) m/s2 4) (24j - 18k) m/s2 5) (24j - 27k) m/s2

1) (36j - 27k) m/s2

What is the radius of curvature of the path of a 3.0-keV proton in a perpendicular magnetic field of magnitude 0.80 T? Question options: 1) 9.9 mm 2) 1.1 cm 3) 1.3 cm 4) 1.4 cm 5) 7.6 mm

1) 9.9 mm

A positively charged particle has a velocity in the negative z direction at point P. The magnetic force on the particle at this point is in the negative y direction. Which one of the following statements about the magnetic field at point P can be determined from this data? Question options: 1) Bx is positive. 2) Bz is positive. 3) By is negative. 4) By is positive. 5) Bx is negative.

1) Bx is positive.

An electron moving in the positive x direction experiences a magnetic force in the positive z direction. If Bx = 0, what is the direction of the magnetic field? Question options: 1) negative y direction 2) positive y direction 3) negative z direction 4) positive z direction 5) negative x direction

1) negative y direction

The algebraic sum of the changes of potential around any closed circuit loop is 1) zero. 2) maximum. 3) zero only if there are no sources of emf in the loop. 4) maximum if there are no sources of emf in the loop. 5) equal to the sum of the currents in the branches of the loop.

1) zero.

When a capacitor is fully charged, the current through the capacitor is 1) zero. 2) at its maximum value. 3) equal to the current in a resistive circuit in parallel with the capacitor circuit. 4) greater than the current in a resistor that is farther from the battery than the capacitor. 5) zero if it is the only capacitor, but maximum if there is another capacitor in series with it.

1) zero.

In an RC circuit, what fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for 3.0 time constants? 1) 0.84 2) 0.90 3) 0.75 4) 0.60 5) 0.03

2) 0.90

What value of wavelength is associated with the Lyman series for n = 2? (RH = 1.097 ´ 107 m-1) Question options: 1) 8.2 ´ 106 m 2) 1.2 ´ 10-7 m 3) 2.7 ´ 106 m 4) 3.6 ´ 10-7 m 5) 8.8 ´ 10-7 m

2) 1.2 ´ 10-7 m

A capacitor in a single-loop RC circuit is charged to 85% of its final potential difference in 2.4 s. What is the time constant for this circuit? 1) 1.5 s 2) 1.3 s 3) 1.7 s 4) 1.9 s 5) 2.9 s

2) 1.3 s

A proton is accelerated from rest through a potential difference of 2.5 kV and then moves perpendicularly through a uniform 0.60-T magnetic field. What is the radius of the resulting path? Question options: 1) 15 mm 2) 12 mm 3) 18 mm 4) 24 mm 5) 8.5 mm

2) 12 mm

A straight 10-cm wire bent at its midpoint so as to form an angle of 90° carries a current of 10 A. It lies in the xy plane in a region where the magnetic field is in the positive z direction and has a constant magnitude of 3.0 mT. What is the magnitude of the magnetic force on this wire? Question options: 1) 3.2 mN 2) 2.1 mN 3) 5.3 mN 4) 4.2 mN 5) 6.0 mN

2) 2.1 mN

A straight wire of length 70 cm carries a current of 50 A and makes an angle of 60° with a uniform magnetic field. If the force on the wire is 1.0 N what is the magnitude of B? Question options: 1) 41 mT 2) 33 mT 3) 55 mT 4) 87 mT 5) 57 mT

2) 33 mT

A charged particle (mass = 4.0 mg, charge = 5.0 mC) moves in a region where the only force on it is magnetic. What is the magnitude of the acceleration of the particle at a point where the speed of the particle is 5.0 km/s, the magnitude of the magnetic field is 8.0 mT, and the angle between the direction of the magnetic field and the velocity of the particle is 60°? Question options: 1) 39 km/s2 2) 43 km/s2 3) 48 km/s2 4) 52 km/s2 5) 25 km/s2

2) 43 km/s2

Charlotte says that you can use a voltmeter to find the current direction in a wire if you can't see the terminals it is connected to. Bonnie says that an ammeter will do. Finally, Rita says that you can bring the north pole of a magnet up to the wire and determine the current direction from the direction of the magnetic force on the wire. Which one(s), if any, is(are) correct? Question options: 1) All three are correct. 2) Charlotte and Rita are correct, but Bonnie is wrong. 3) Bonnie and Rita are correct, but Charlotte is wrong. 4) Charlotte and Bonnie are correct, but Rita is wrong. 5) Only Rita is correct.

2) Charlotte and Rita are correct, but Bonnie is wrong

Bert says that a charged particle in a vacuum can travel in a helix only if a uniform electric field and a uniform magnetic field are both present and both parallel to the axis of the helix. Stuart says that only a magnetic field with a component parallel to the axis of the helix is needed. Which one, if either, is correct, and why? Question options: 1) Bert, because the charged particle's velocity can have a vertical component only if an electric field in the vertical direction is present. 2) Stuart, because a component of velocity in the vertical direction is not changed by a vertical component of a magnetic field. 3) Bert, because a component of velocity in the vertical direction is changed by a vertical component of a magnetic field. 4) Stuart, because an electric field in the vertical direction would cause the particle to come to a complete stop. 5) Neither, because particles cannot move in helical paths in the presence of magnetic and electric fields.

2) Stuart, because a component of velocity in the vertical direction is not changed by a vertical component of a magnetic field

An explorer walks into a lab in a science building. She has a compass in her hand and finds that the south pole of her compass points toward the room's East wall when she is nearer that wall and toward the west wall when she is nearer that wall. You could explain this if magnetized metal had been installed in the East and West walls with North poles pointing into the room. If no magnetic material was installed in the North or South walls of the room, she would expect that Question options: 1) the south pole of the compass would tend to point toward those walls. 2) the north pole of the compass would tend to point toward those walls. 3) the compass needle would not point in any particular direction. 4) the north pole of the compass needle would tend to point toward the centers of those walls, but the south pole would tend to point toward the sides of those walls. 5) the south pole of the compass needle would tend to point toward the centers of those walls, but the north pole would tend to point toward the sides of those walls.

2) the north pole of the compass would tend to point toward those walls.

A particle (mass = 6.0 mg) moves with a speed of 4.0 km/s in a direction that makes an angle of 37° above the positive x axis in the xy plane. At the instant it enters a magnetic field of (5.0i) mT it experiences an acceleration of (8.0k) m/s2. What is the charge of the particle? Question options: 1) -4.8 mC 2) 4.0 mC 3) -4.0 mC 4) 4.8 mC 5) -5.0 mC

3) -4.0 mC

A charged particle moves in a region of uniform magnetic field along a helical path (radius = 4.0 cm, pitch = 20 cm, period = 2.0 ms). What is the speed of the particle as it moves along this path? Question options: 1) 0.13 km/s 2) 0.10 km/s 3) 0.16 km/s 4) 0.23 km/s 5) 0.06 km/s

3) 0.16 km/s

A current of 4.0 A is maintained in a single circular loop having a circumference of 80 cm. An external magnetic field of 2.0 T is directed so that the angle between the field and the plane of the loop is 20°. Determine the magnitude of the torque exerted on the loop by the magnetic forces acting upon it. Question options: 1) 0.41 N × m 2) 0.14 N × m 3) 0.38 N × m 4) 0.27 N × m 5) 0.77 N × m

3) 0.38 N × m

A circular coil (radius = 0.40 m) has 160 turns and is in a uniform magnetic field. When the orientation of the coil is varied through all possible positions, the maximum torque on the coil by magnetic forces is 0.16 N × m when the current in the coil is 4.0 mA. What is the magnitude of the magnetic field? Question options: 1) 0.37 T 2) 1.6 T 3) 0.50 T 4) 1.2 T 5) 2.5 T

3) 0.50 T

What is the magnetic force on a 2.0-m length of (straight) wire carrying a current of 30 A in a region where a uniform magnetic field has a magnitude of 55 mT and is directed at an angle of 20° away from the wire? Question options: 1) 1.5 N 2) 1.3 N 3) 1.1 N 4) 1.7 N 5) 3.1 N

3) 1.1 N

A 500-eV electron and a 300-eV electron trapped in a uniform magnetic field move in circular paths in a plane perpendicular to the magnetic field. What is the ratio of the radii of their orbits? Question options: 1) 2.8 2) 1.7 3) 1.3 4) 4.0 5) 1.0

3) 1.3

In an RC circuit, how many time constants must elapse if an initially uncharged capacitor is to reach 80% of its final potential difference? 1) 2.2 2) 1.9 3) 1.6 4) 3.0 5) 5.0

3) 1.6

A proton is accelerated from rest through a potential difference of 150 V. It then enters a region of uniform magnetic field and moves in a circular path (radius = 12 cm). What is the magnitude of the magnetic field in this region? Question options: 1) 18 mT 2) 12 mT 3) 15 mT 4) 22 mT 5) 10 mT

3) 15 mT

A deuteron is accelerated from rest through a 10-kV potential difference and then moves perpendicularly to a uniform magnetic field with B = 1.6 T. What is the radius of the resulting circular path? (deuteron: m = 3.3 ´ 10-27 kg, q = 1.6 ´ 10-19 C) Question options: 1) 19 mm 2) 16 mm 3) 20.3 mm 4) 10 mm 5) 9.0 mm

3) 20.3 mm

Two single charged ions moving perpendicularly to a uniform magnetic field (B = 0.4 T) with speeds of 5000 km/s follow circular paths that differ in diameter by 5.0 cm. What is the difference in the mass of these two ions? Question options: 1) 2.6 ´ 10-28 kg 2) 6.4 ´ 10-28 kg 3) 3.2 ´ 10-28 kg 4) 5.1 ´ 10-28 kg 5) 1.1 ´ 10-28 kg

3) 3.2 ´ 10-28 kg

A proton with a kinetic energy of 0.20 keV follows a circular path in a region where the magnetic field is uniform and has a magnitude of 60 mT. What is the radius of this path? Question options: 1) 4.1 cm 2) 2.9 cm 3) 3.4 cm 4) 5.1 cm 5) 2.4 cm

3) 3.4 cm

An electron moves in a region where the magnetic field is uniform, has a magnitude of 60 mT, and points in the positive x direction. At t = 0 the electron has a velocity that has an x component of 30 km/s, a y component of 40 km/s, and a z component of zero. What is the radius of the resulting helical path? Question options: 1) 4.7 mm 2) 18 mm 3) 3.8 mm 4) 2.8 mm 5) 5.7 mm

3) 3.8 mm

A particle (q = 5.0 nC, m = 3.0 mg) moves in a region where the magnetic field has components Bx = 2.0 mT, By = 3.0 mT, and Bz = -4.0 mT. At an instant when the speed of the particle is 5.0 km/s and the direction of its velocity is 120° relative to the magnetic field, what is the magnitude of the acceleration of the particle? Question options: 1) 33 m/s2 2) 17 m/s2 3) 39 m/s2 4) 25 m/s2 5) 45 m/s2

3) 39 m/s2

A rectangular coil (0.20 m ´ 0.80 m) has 200 turns and is in a uniform magnetic field of 0.30 T. When the orientation of the coil is varied through all possible positions, the maximum torque on the coil by magnetic forces is 0.080 N × m. What is the current in the coil? Question options: 1) 5.0 mA 2) 1.7 A 3) 8.3 mA 4) 1.0 A 5) 42 mA

3) 8.3 mA

A charged particle (mass = M, charge = Q > 0) moves in a region of space where the magnetic field has a constant magnitude of B and a downward direction. What is the magnetic force on the particle at an instant when it is moving horizontally toward the north with a speed V? Question options: 1) QVB toward the east 2) Zero 3) QVB toward the west 4) QVB upward 5) QVB toward the south

3) QVB toward the west

A charged particle (mass = M, charge = Q > 0) moves in a region of space where the magnetic field has a constant magnitude of B and a downward direction. What is the magnetic force on the particle at an instant when it is moving horizontally toward the north with speed V? Question options: 1) QVB toward the east 2) Zero 3) QVB toward the west 4) QVB upward 5) QVB toward the south

3) QVB toward the west

Radiant energy reaching the Earth from the sun is not sufficient to keep the Earth's surface temperature comfortable for life. The most likely source of the additional thermal energy is from Question options: 1) fusion of hydrogen nuclei in the Earth's core. 2) fusion of high Z nuclei in the Earth's core. 3) fission of radioactive nuclei inside the Earth. 4) fission of radioactive nuclei in cosmic rays. 5) deflection of radioactive nuclei in cosmic rays.

3) fission of radioactive nuclei inside the Earth.

You stand near the earth's equator. A positively charged particle that starts moving parallel to the surface of the earth in a straight line directed east is initially deflected upwards. If you know there are no electric fields in the vicinity, a possible reason why the particle does not initially acquire a downward component of velocity is because near the equator the magnetic field lines of the earth are directed Question options: 1) upward. 2) downward. 3) from south to north. 4) from north to south. 5) from east to west.

3) from south to north.

The battery is disconnected from a series RC circuit after the capacitor is fully charged and is replaced by an open switch. When the switch is closed, 1) the current through the resistor is always greater than the current through the capacitor. 2) the current through the resistor is always less than the current through the capacitor. 3) the current through the resistor is always equal to the current through the capacitor. 4) the capacitor does not allow current to pass. 5) the current stops in the resistor.

3) the current through the resistor is always equal to the current through the capacitor.

When a fast neutron collides with a hydrogen or deuterium nucleus, the most likely result is that Question options: 1) the neutron has an appreciable gain in kinetic energy, the gain being greatest for head-on collisions. 2) the neutron has an appreciable gain in kinetic energy, the gain being greatest for oblique collisions. 3) the neutron has an appreciable loss in kinetic energy, the loss being greatest for head-on collisions. 4) the neutron has an appreciable loss in kinetic energy, the loss being greatest for oblique collisions. 5) the neutron is absorbed by the hydrogen or deuterium nucleus.

3) the neutron has an appreciable loss in kinetic energy, the loss being greatest for head-on collisions.

In neutron capture by an atomic nucleus, the mass number of the nucleus changes by Question options: 1) -2. 2) -1. 3) 0. 4) +1. 5) +2.

4) +1.

A thermal neutron has an energy (in eV) on the order of Question options: 1) 40 2) 0.4 3) 4 4) 0.04 5) 400

4) 0.04

Calculate the half-value thickness (in mm) of lead if it reduces the intensity of a beam of x-rays whose wavelength is 10 pm by a factor of two. (The linear absorption coefficient of lead is 43 cm-1 for x-rays of wavelength 60 ´ 10-12 m.) Question options: 1) 0.24 2) 0.20 3) 0.12 4) 0.16 5) 0.18

4) 0.16

An unusual lightning strike has a vertical portion with a positive current of +400 A upwards. The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 mT. In N, the force exerted by the Earth's magnetic field on the 25 m-long current is Question options: 1) 0. 2) 0.012 A, East. 3) 0.012 A, West. 4) 0.30 A, West. 5) 300 A, East.

4) 0.30 A, West.

A straight wire of length L carries a current I in the positive z direction in a region where the magnetic field is uniform and specified by Bx = 3B, By = -2B, and Bz = B, where B is a constant. What is the magnitude of the magnetic force on the wire? Question options: 1) 3.2 ILB 2) 5.0 ILB 3) 4.2 ILB 4) 3.6 ILB 5) 1.0 ILB

4) 3.6 ILB

An electron moves in a region where the magnetic field is uniform and has a magnitude of 80 mT. The electron follows a helical path which has a pitch of 9.0 mm and a radius of 2.0 mm. What is the speed of this electron as it moves in this region? Question options: 1) 48 km/s 2) 28 km/s 3) 20 km/s 4) 35 km/s 5) 8.0 km/s

4) 35 km/s

A particle (q = -4.0 mC, m = 5.0 mg) moves in a uniform magnetic field with a velocity having a magnitude of 2.0 km/s and a direction that is 50° away from that of the magnetic field. The particle is observed to have an acceleration with a magnitude of 5.8 m/s2. What is the magnitude of the magnetic field? Question options: 1) 5.3 mT 2) 4.9 mT 3) 5.1 mT 4) 4.7 mT 5) 3.6 mT

4) 4.7 mT

A proton moves around a circular path (radius = 2.0 mm) in a uniform 0.25-T magnetic field. What total distance does this proton travel during a 1.0-s time interval? (m = 1.67 ´ 10-27 kg, q = 1.6 ´ 10-19 C) Question options: 1) 82 km 2) 59 km 3) 71 km 4) 48 km 5) 7.5 km

4) 48 km

What current must be maintained in a square loop (50 cm on a side) to create a torque of 1.0 N × m about an axis through its center and parallel to one of its sides when a magnetic field of magnitude 70 mT is directed at 40° to the plane of the loop? Question options: 1) 66 A 2) 89 A 3) 61 A 4) 75 A 5) 37 A

4) 75 A

A circular loop (radius = 0.50 m) carries a current of 3.0 A and has unit normal vector of (2i - j + 2k)/3. What is the x component of the torque on this loop when it is placed in a uniform magnetic field of (2i - 6j)T? Question options: 1) 4.7 N × m 2) 3.1 N × m 3) 19 N × m 4) 9.4 N × m 5) 12 N × m

4) 9.4 N × m

Equal charges, one at rest, the other having a velocity of 104 m/s, are released in a uniform magnetic field. Which charge has the largest force exerted on it by the magnetic field? Question options: 1) The charge that is at rest. 2) The charge that is moving, if its velocity is parallel to the magnetic field direction when it is released. 3) The charge that is moving if its velocity makes an angle of 45o with the direction of the magnetic field when it is released. 4) The charge that is moving if its velocity is perpendicular to the magnetic field direction when it is released. 5) All the charges above experience equal forces when released in the same magnetic field.

4) The charge that is moving if its velocity is perpendicular to the magnetic field direction when it is released.

A rem (roentgen equivalent in man) is defined as (the product of) Question options: 1) the dose in RBE. 2) the dose in roentgen and the RBE factor. 3) the dose in rad times the dose in roentgen. 4) the dose in rad and the RBE factor. 5) the dose in rad and energy of radiation.

4) the dose in rad and the RBE factor.

In an atom that has an electron in a sub-shell for which = 4, with respect to the magnetic field vector B the magnetic moment vector m of the electron is allowed to be oriented in Question options: 1) any direction. 2) discrete directions 3) - 1 discrete directions. 4) + 1 discrete directions. 5) 2 + 1 discrete directions.

5) 2 + 1 discrete directions.

Aline says that the magnetic moment of an atom originates in the orbital angular momentum of the electron. Bevis says that it comes from the electron spin. Which one, if either, is correct, and why? Question options: 1) Aline, because only atoms, not electrons, can have angular momentum. 2) Bevis, because only atoms, not electrons, can have angular momentum. 3) Neither, because electron spin and orbital angular momentum always cancel exactly. 4) Neither, because the magnetic moment of an atom comes only from the spin of the nucleus. 5) Both, because both the orbital angular momentum and the spins of the electrons contribute to the magnetic moment of an atom.

5) Both, because both the orbital angular momentum and the spins of the electrons contribute to the magnetic moment of an atom.

In order to control a nuclear reactor, control rods can be pulled out of or pushed into the reactor core by remote control. These rods control the reactor by Question options: 1) slowing down the fast neutrons so the neutrons can be absorbed by 238U. 2) speeding up slow neutrons so the neutrons can be absorbed by 238U. 3) slowing down fast neutrons so they cannot initiate further fusion reactions in 235U. 4) speeding up fast neutrons so they cannot initiate further fusion reactions in 235U. 5) capturing thermal neutrons so they cannot initiate further fission reactions in 235U.

5) capturing thermal neutrons so they cannot initiate further fission reactions in 235U.

The intensity of radiation reaching the earth from the sun is 1350 W/m2. The earth's radius is 6.4 × 106 m. How big a force does this radiation exert on the earth? (Assume it is all absorbed.) a.! 5.8 × 108 N b.! 1.2 × 109 N c.! 2.3 × 109 N d.! 4.6 × 109 N e.! 1.7 × 1017 N

a.! 5.8 × 108 N

A layer of ethyl alcohol (n = 1.361) is on top of water (n = 1.333). At what angle relative to the normal to the interface of the two liquids is light totally reflected? a.! 78° b.! 88° c.! 68° d.! 49° e.! the critical angle is undefined

a.! 78°

A 100-kW radio station emits EM waves in all directions from an antenna on top of a mountain. What is the intensity of the signal at a distance of 10 km? a.! 8 × 10-5 W/m2 b.! 8 × 10-6 W/m2 c.! 3 × 10-3 W/m2 d.! 0.8 W/m2 e.! 2.5 × 10-5 W/m2

a.! 8 × 10-5 W/m2

Light behaves like a.! a wave at times, and a particle at other times. b.! a wave. c.! a particle. d.! both a wave and a particle, because of its dual nature.

a.! a wave at times, and a particle at other times.

Find the resonant frequency for a series RLC circuit where R = 10Ω, C = 5 µF, and L = 2 mH. a.! 998 Hz b.! 1.592 kHz c.! 2.45 kHz d.! 11.3 kHz e.! 2.53 kHz

b. 1.592 kHz

A step-up transformer has an input voltage of 110V(rms). There are 100 turns on the primary and 1500 on the secondary. What is the output voltage? a.! 1600 V (max) b.! 1650 V (rms) c.! 3260 V (max) d.! 165 kV (rms) e.! 7.3 V (rms)

b. 1650 V (rms)

What is the average power dissipation in a series RC circuit if R = 5 kΩ, C = 2 µF, and V = 170 cos (300t)? a.! 0.93 W b.! 2.60 W c.! 28.2 W d.! 157 W e.! 5.20 W

b. 2.60 W

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface. The edges of the two mirrors meet at a angle. A light ray that enters parallel to mirror 2 reflects from mirror 1 and then from mirror 2. The angle of reflection of that ray from mirror 2 is a. 0 b. 30 c. 60 d. 90 e. 120

b. 30

The inductance of a tuning circuit of an AM radio is 4 mH. Find the capacitance of the circuit required for reception at 1200 kHz. a.! 2.1 pF b.! 4.4 pF c.! 21.2 pF d.! 43.4 pF e.! 27.6 pF

b. 4.4 pF

An RLC series circuit has R = 100 ohms, C = 25 µF, and L = 0.16 H. For what angular frequency of an ac voltage is the current flow maximum? a.! 251 rad/s b.! 500 rad/s c.! 757 rad/s d.! 884 rad/s e.! 79.6 rad/s

b. 500 rad/s

If the radiant energy from the sun comes in as a plane EM wave of intensity 1340 W/m2, calculate the peak values of E and B. a.! 300 V/m, 10-4 T b.! 1000 V/m, 3.35 × 10-6 T c.! 225 V/m, 1.6 × 10-3 T d.! 111 V/m, 3 × 10-5 T e.! 711 V/m, 2.37 × 10-6 T

b.! 1000 V/m, 3.35 × 10-6 T

Light is refracted through a diamond. If the angle of incidence is 30°, and the angle of refraction is 12°, what is the index of refraction? a.! 1.3 b.! 2.4 c.! 2.6 d.! 1.8 e.! 0.4

b.! 2.4

An aquarium contains a 5-cm layer of water (n = 1.333) floating on top of carbon tetrachloride (n = 1.461). If the angle of incidence into the water from the carbon tetrachloride is 20°, what is the angle of refraction into the air? a.! 20° b.! 30° c.! 38° d.! 69° e.! 26°

b.! 30°

A person looks horizontally at the edge of a swimming pool. If its length is 5 m, and the pool is filled to the surface, to what depth (in m) could the observer see? (n for water is 1.33) a.! 3.2 b.! 4.4 c.! 2.1 d.! 1.0 e.! 0.3

b.! 4.4

A 60-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with . The power factor, is a.! -1.00. b.! -0.749. c.! +0.749. d.! +0.834. e.! +1.00.

c. 0.749 In a parallel RLC circuit, where Ir = Ir,max(sin(wt)) , the current through the inductor, IL, is a. IL = -IL,max(sin(wt)). b. IL = IL,max(sin(wt)). c. IL = -IL,max(cos(wt)). d. IL = IL,max(cos(wt)). e. IL = IL,max(tan(wt)).~c. IL = -IL,max(cos(wt)).

A 0.5-H inductor is connected into a 110 V-rms 60-Hz voltage source, with an ammeter in series. What is the rms value of the current through the inductor? a.! 0.189 A (rms) b.! 0.292 A (rms) c.! 0.584 A (rms) d.! 1.19 A (rms) e.! 0.093 A (rms)

c.! 0.584 A (rms)

The speed of light changes when it goes from ethyl alcohol (n = 1.361) to carbon tetrachloride (n = 1.461). The ratio of the speed in carbon tetrachloride to the speed in ethyl alcohol, v2/v1, is a.! 1.99 b.! 1.07 c.! 0.93 d.! 0.51 e.! 0.76

c.! 0.93

What is the average power dissipation in an RLC series circuit with R = 10Ω, L = 0.1 H, C = 10 µF when driven at resonance by a 100 V-rms source? a.! 100 W b.! 500 W c.! 1000 W d.! 2 kW e.! 700 W

c.! 1000 W

If the maximum E-component of an electromagnetic wave is 600 V/m, what is the maximum B-component? a.! 1.4 T b.! 1.8 × 10-5 T c.! 2.0 × 10-6 T d.! 1.0 × 10-3 T e.! 1.6 × 10-10 T

c.! 2.0 × 10-6 T

An experiment to measure the speed of light uses an apparatus similar to Fizeau's. The distance between the light source and the mirror is 10 m, and the wheel has 800 notches. If the wheel rotates at 9000 rev/s when the light from the source is extinguished, what is the experimental value for c (in m/s)? a.! 2.94 × 108 b.! 2.92 × 108 c.! 2.88 × 108 d.! 2.98 × 108 e.! 3.01 × 108

c.! 2.88 × 108

The voltage 8.00 sin (400t) is applied to a series RLC circuit, with R = 200Ω, L = 0.100 H, and C = 1.00 µF. What are the impedance Z and the phase angle θ? a.! 200 Ω, -37° b.! 566 Ω, +87° c.! 2470 Ω, -85.4° d.! 2540 Ω, -88.8° e.! 393 Ω, -63°

c.! 2470 Ω, -85.4°

An FM radio station broadcasts at 98.6 MHz. What is the wavelength of the radiowaves? a.! 60.8 m b.! 6.08 m c.! 3.04 m d.! 0.314 m e.! 0.33 cm

c.! 3.04 m

Light strikes a diamond (n = 2.42) immersed in glycerin (n = 1.473) at an angle of 60° relative to the normal to the surface. What is the angle of refraction? a.! 20° b.! 60° c.! 32° d.! 64° e.! 15°

c.! 32°

A diver shines light up to the surface of a flat glass-bottomed boat at an angle of 30° relative to the normal. If the index of refraction of water and glass are 1.33 and 1.5, respectively, at what angle (in degrees) does the light leave the glass (relative to its normal)? a.! 26 b.! 35 c.! 42 d.! 22 e." 48

c.! 42

An ac generator with peak voltage 100 volts is placed across a 10-Ω resistor. What is the average power dissipated? a.! 100 W b.! 150 W c.! 500 W d.! 1000 W e.! 2000 W

c.! 500 W

If an R = 1-kΩ resistor, a C = 1-µF capacitor, and an L = 0.2-H inductor are connected in series with a V = 150 sin (377t) volts source, what is the maximum current delivered by the source? a.! 0.007 A b.! 27 mA c.! 54 mA d.! 0.308 A e.! 0.34 A

c.! 54 mA

A layer of water (n = 1.333) floats on carbon tetrachloride (n = 1.461) contained in an aquarium. What is the critical angle at the interface between the two liquids? a.! 88° b.! 78° c.! 66° d.! 58° e.! 43°

c.! 66°

What is the maximum radiation pressure exerted by sunlight in space (S = 1350 W/m2) on a highly polished silver surface? a.! 1.4 × 10-2 Pa b.! 0.12 Pa c.! 9.0 × 10-6 Pa d.! 4.5 × 10-5 Pa e.! 2.3 × 10-6 Pa

c.! 9.0 × 10-6 Pa

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface. A light ray that reflects from mirror 1 at angle THETA_m1 then strikes the second mirror and reflects at THETA_m2 such that the angle between the ray reaching mirror 1 and the ray leaving mirror 2 is 180 DEGREES. The angle between the two mirrors is a.! 0 b.! 45 c.! 90 d.!. 180 e.!. 235

c.! 90

An incandescent lightbulb is rated at 100 Watts when plugged into a 110 V-rms household outlet. Calculate the resistance of the filament and the rms current. a.! 12.2Ω, 0.90 A (rms) b.! 10Ω, 1.0 A (rms) c.! 110Ω, 1.0 A (rms) d.! 121Ω, 0.90 A (rms) e. 11Ω, 1.1 A (rms)

d.! 121Ω, 0.90 A (rms)

An ideal step-down transformer has 200 primary turns and 50 secondary turns. If 440 volts (rms) is placed across the primary, what is the current in the secondary when the load resistance is 7 ohms? a.! 3.6 A (rms) b.! 7.3 A (rms) c.! 11.4 A (rms) d.! 15.7 A (rms) e.! 12.4 A (rms)

d.! 15.7 A (rms)

At what frequency will a 50-mH inductor have a reactance XL = 700Ω? a.! 352 Hz b.! 777 Hz c.! 1.25 kHz d.! 2.23 kHz e.! 14 kHz

d.! 2.23 kHz

A high-voltage powerline operates at 500 000 V-rms and carries an rms current of 500 A. If the resistance of the cable is 0.050Ω/km, what is the resistive power loss in 200 km of the powerline? a.! 250 kW b.! 500 kW c.! 1 Megawatt d.! 2.5 Megawatts e.! 250 Megawatts

d.! 2.5 Megawatts

A light ray is incident on the surface of water (n = 1.33) at an angle of 60° relative to the normal to the surface. The angle of the reflected wave is a.! 80° b.! 40° c.! 20° d.! 60° e.! 30°

d.! 60°

What should be the height of a dipole antenna (of dimensions 1/4 wavelength) if it is to transmit 1200 kHz radiowaves? a.! 11.4 m b.! 60 cm c.! 1.12 m d.! 62.5 m e.! 250 m

d.! 62.5 m

What is the average value of the magnitude of the Poynting vector S at 1 meter from a 100-watt lightbulb radiating in all directions? a.! 1 W/m2 b.! 4 W/m2 c.! 2 W/m2 d.! 8 W/m2 e.! 12 W/m2

d.! 8 W/m2

A primary current of 6 A exists in an ideal iron-core transformer at a primary voltage of 100 volts. If the current in the secondary is 0.75 A, calculate the output voltage. a.! 12.5 V b.! 40 V c.! 400 V d.! 800 V e.! 200 V

d.! 800 V

In a typical transmission line, the current I is very small and the voltage V is very large. A unit length of line has resistance R. For a power line that supplies power to 10,000 households, we can conclude that a.! IV = I2R. b.! I = V/R. c.! IV < I2R. d.! IV > I2R. e.! I2R = 0.

d.! IV > I2R.

High frequency alternating current is passed through a solenoid that contains a solid copper core insulated from the coils of the solenoid. Which statement is correct? a.! A copper core remains cool no matter what the frequency of the current in the solenoid is. b.! The copper core remains cool because the induced emf is parallel to the solenoid axis and fluctuates rapidly. c.! The copper core heats up because an emf parallel to the solenoid axis is induced in the core. d.! The copper core heats up because circular currents around its axis are induced in the core. e.! The copper core heats up because the electric field induced in the copper is parallel to the magnetic field produced by the solenoid.

d.! The copper core heats up because circular currents around its axis are induced in the core.

An alternating current circuit has resistance R, inductance L and capacitance C in series with a voltage source. Which statement is correct? a.! The voltage across the capacitor leads the voltage across the inductor by 90°. b.! The voltage across the inductor leads the voltage across the capacitor by 90°. c.! The voltage across the inductor leads the voltage across the resistor by 180°. d.! The voltage across the inductor leads the voltage across the capacitor by 180°. e.! Both voltages lead the voltage across the resistor by 90°.

d.! The voltage across the inductor leads the voltage across the capacitor by 180°

In the atmosphere, the shortest wavelength electromagnetic waves are called a.! microwaves. b.! infrared waves. c.! ultraviolet waves. d.! X-rays. e.! gamma rays.

e.! gamma rays.

The average power input to a series alternating current circuit is minimum when a.! there are only a resistor and capacitor in the circuit. b.! there are only a resistor and inductor in the circuit. c.! there is only a resistor in the circuit. d.! XL = XC and the circuit contains a resistor, an inductor and a capacitor. e.! there is only a capacitor in the circuit.

e.! there is only a capacitor in the circuit.

When a light ray travels between any two points, the path it takes is the one that a." covers the greatest distance. b." follows the greatest index of refraction. c." avoids travel in more than one medium. d." is the mean between the longest and the shortest paths. e." takes the least time.

e." takes the least time.