Physics 2 Review CAS
A cylindrical wire has a resistance R and resistivity ρ. If its length and diameter are BOTH cut in half, (a) what will be its resistance? A) 4R B) 2R C) R D) R/2 E) R/4 (b) what will be its resistivity? A) 4ρ B) 2ρ C) ρ D) ρ/2
(a) B) 2R (b) C) ρ
A current carrying loop of wire lies flat on a table top. When viewed from above, the current moves around the loop in a counterclockwise sense. (a) For points OUTSIDE the loop, the magnetic field caused by this current A.) circles the loop in a clockwise direction. B.) circles the loop in a counterclockwise direction. C.) points straight up. D.) points straight down. E.) is zero. (b) For points INSIDE the loop, the magnetic field caused by this current A.) circles the loop in a clockwise direction. B. ) circles the loop in a counterclockwise direction. C.) points straight up. D.) points straight down. E.) is zero.
(a) D.) points straight down. (b) C.) points straight up.
Two very large, flat plates are parallel to each other. Plate A, located at y = 1.0 cm, is along the xz-plane and carries a uniform surface charge density -1.00 μC/m2. Plate B is located at y = -1.0 cm and carries a uniform surface charge density +2.00 μC/m2. What is the electric field vector at the point having x, y, z coordinates (-0.50 cm, 0.00 cm, 0.00 cm)? (ε0 = 8.85 × 10^-12 C2/N · m2) A) (+1.13 × 10^5 N/C) î B) (-2.83 × 10^5 N/C) j C) (+1.19 × 10^5 N/C) j D) (+1.69 × 10^5 N/C) j E) (-1.19 × 10^5 N/C) j
A) (+1.13 × 10^5 N/C) î
At a distance of 4.3 cm from the center of a very long uniformly charged wire, the electric field has magnitude 2000 N/C and is directed toward the wire. What is the charge on a 1.0 cm length of wire near the center? ( ε0 = 8.85 × 10^-12 C2/N · m2) A) -0.048 nC B) -0.052 nC C) -0.044 nC D) -0.056 nC
A) -0.048 nC
The electric field 1.5 cm from a very small charged object points toward the object with a magnitude of 180,000 N/C. What is the charge on the object? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) -4.5 nC B) +4.5 nC C) -5.0 nC D) +5.0 nC
A) -4.5 nC
A charged particle of mass 0.0020 kg is subjected to a 6.0 T magnetic field which acts at a right angle to its motion. If the particle moves in a circle of radius 0.20 m at a speed of 5.0 m/s, what is the magnitude of the charge on the particle? A) 0.0083 C B) 120 C C) 0.00040 C D) 2500 C
A) 0.0083 C
An electric dipole is made of two charges of equal magnitudes and opposite signs. The positive charge, q = 1.0 μC, is located at the point (x, y, z) = (0.00 cm, 1.0 cm, 0.00 cm), while the negative charge is located at the point (x, y, z) = (0.00 cm, -1.0 cm, 0.00 cm). How much work will be done by an electric field E = (3.0 × 106 N/C) î to bring the dipole to its stable equilibrium position? A) 0.060 J B) 0.030 J C) 0.00 J D) 0.020 J E) 0.12 J
A) 0.060 J
An air-filled capacitor stores a potential energy of 6.00 mJ due to its charge. It is accidentally filled with water in such a way as not to discharge its plates. How much energy does it continue to store after it is filled? (The dielectric constant for water is 78 and for air it is 1.0006.) A) 0.077 mJ B) 468 mJ C) 0.040 mJ D) 6.00 mJ
A) 0.077 mJ
A circular coil of wire of 200 turns and diameter 2.0 cm carries a current of 4.0 A. It is placed in a magnetic field of 0.70 T with the plane of the coil making an angle of 30 ° with the magnetic field. What is the magnetic torque on the coil? A) 0.15 N · m B) 0.088 N·m C) 0.29 N · m D) 0.40 N · m E) 0.076 N·m
A) 0.15 N · m
Alpha particles (charge = +2e, mass = 6.68 × 10^-27 kg, e = 1.60 × 10^-19 C) are accelerated in a cyclotron to a final orbit radius of 0.90 m. The magnetic field in the cyclotron is 0.30 T. The period of the circular motion of the alpha particles is closest to ________. A) 0.44 μs. B) 0.67 μs. C) 0.87 μs. D) 1.1 μs. E) 1.3 μs.
A) 0.44 μs.
A dipole with a positive charge of 2.0 μC and a negative charge of -2.0 μC is centered at the origin and oriented along the x-axis with the positive charge located to the right of the origin. The charge separation is 0.0010 m. Find the electric field due to this dipole at the point x=4.0m,y=0.0m.(k=1/4πε0 =8.99×10^9N·m2/C2) A) 0.56 î N/C B) -0.56 î N/C C) 0.28 î N/C D) -0.28 î N/C
A) 0.56 î N/C
If the intensity of an electromagnetic wave is 80 MW/m2, what is the amplitude of the magnetic field of this wave? (c = 3.0 x 10^8 m/s, μ0 = 4π × 10^-7 T · m/A, ε0 = 8.85 × 10^-12 C^2/N · m^2) A) 0.82 mT B) 0.33 μT C) 10 T D) 14 T E) 0.58 mT
A) 0.82 mT
A small sphere with a mass of 441 g is moving upward along the vertical +y-axis when it encounters an electric field of 5.00 N/C ^i. If, due to this field, the sphere suddenly acquires a horizontal acceleration of 13.0 m/s2 î, what is the charge that it carries? A) 1.15 C B) ‐1.15 C C) 1150 C D) ‐1150 C
A) 1.15 C
Two small insulating spheres are attached to silk threads and aligned vertically as shown in the figure. These spheres have equal masses of 40 g, and carry charges q1 and q2 of equal magnitude 2.0 μC but opposite sign. The spheres are brought into the positions shown in the figure, with a vertical separation of 15 cm between them. Note that you cannot neglect gravity. (k = 1/4πε0 = 8.99 × 109 N · m2/C2) The tension in the lower thread is closest to A) 1.2 N. B) 1.4 N. C) 1.6 N. D) 1.8 N. E) 2.0 N.
A) 1.2 N.
A piece of plastic has a net charge of +2.00 μC. How many more protons than electrons does this piece of plastic have? (e = 1.60 × 10-19 C) A) 1.25 × 10^13 B) 1.25 × 10^19 C) 2.50 × 10^13 D) 2.50 × 10^19
A) 1.25 × 10^13
A small glass bead has been charged to 8.0 nC. What is the magnitude of the electric field 2.0 cm from the center of the bead? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 1.8 × 10^5 N/C B) 3.6 × 10^3 N/C C) 1.4 × 10^-3 N/C D) 3.6 × 10^-6 N/C
A) 1.8 × 10^5 N/C
A parallel-plate capacitor consists of two parallel, square plates that have dimensions 1.0 cm by 1.0 cm. If the plates are separated by 1.0 mm, and the space between them is filled with teflon, what is the capacitance of this capacitor? (The dielectric constant for teflon is 2.1, and ε0 = 8.85 × 10^-12 C^2/N · m^2.) A) 1.9 pF B) 0.44 pF C) 2.1 pF D) 0.89 pF
A) 1.9 pF
A doubly charged ion (charge 2e) with velocity 6.9 × 10^6 m/s moves in a circular path of diameter 60.0 cm in a magnetic field of 0.80 T in a mass spectrometer. What is the mass of this ion? ( e = 1.60 × 10^-19 C) A) 11 × 10^-27 kg B) 6.7 × 10^-27 kg C) 4.5 × 10^-27 kg D) 3.3 × 10^-27 kg E) 8.2 × 10^-27 kg
A) 11 × 10^-27 kg
A sphere with radius 2.0 mm carries +1.0 μC of charge distributed uniformly throughout its volume. What is the potential difference, VB - VA, between point B, which is 4.0 m from the center of the sphere, and point A, which is 9.0 m from the center of the sphere? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 1200 V B) ‐1200 V C) 140 V D) ‐0.45 V
A) 1200 V
Each plate of an air-filled parallel-plate air capacitor has an area of 0.0040 m^2, and the separation of the plates is 0.080 mm. An electric field of 5.3 × 10^6 V/m is present between the plates. What is the energy density between the plates? (ε0 = 8.85 × 10^-12 C^2/N · m^2) A) 124 J/m^3 B) 84 J/m^3 C) 170 J/m^3 D) 210 J/m^3 E) 250 J/m3
A) 124 J/m^3
A series circuit consists of ac source, a 90-Ω resistor, a 0.80-H inductor, and an 80-μF capacitor. The frequency of the source is adjusted so that the capacitive reactance is equal to twice the inductive reactance. What is the frequency of the source? A) 14 Hz B) 13 Hz C) 16 Hz D) 17 Hz E) 19 Hz
A) 14 Hz
A 1.0 μF capacitor has a potential difference of 6.0 V applied across its plates. If the potential difference across its plates is increased to 8.0 V, how much ADDITIONAL energy does the capacitor store? A) 14 μJ B) 28 μJ C) 2.0 μJ D) 4.0 μJ
A) 14 μJ
The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.939 W/m 2. The wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. How much total electromagnetic energy falls on the area during 1.0 minute? (c = 3.0 x 10^8 m/s, μ0 = 4π × 10^-7 T · m/A, ε0 = 8.85 × 10^-12 C^2/N · m^2) A) 170 J B) 210 J C) 250 J D) 300 J E) 340 J
A) 170 J
A very small object carrying -6.0 μC of charge is attracted to a large, well-anchored, positively charged object. How much kinetic energy does the negatively charged object gain if the potential difference through which it moves is 3.0 mV? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 18 nJ B) 0.50 kJ C) 0.50 J D) 6.0 μJ
A) 18 nJ
An alpha particle is a nucleus of helium. It has twice the charge and four times the mass of the proton. When they were very far away from each other, but headed toward directly each other, a proton and an alpha particle each had an initial speed of 0.0030c, where c is the speed of light. What is their distance of closest approach? Hint: There are two conserved quantities. Make use of both of them. (c = 3.00 × 10^8 m/s, k = 1/4πε0 = 8.99 × 10^9 N · m2/C2, e = 1.60 × 10^-19 C, mproton = 1.67 x 10^-27 kg) A) 2.1 × 10^-13 m B) 3.3 × 10^-13 m C) 2.6 × 10^-13 m D) 2.9 × 10^-13 m
A) 2.1 × 10^-13 m
An electron enters a magnetic field of 0.75 T with a velocity perpendicular to the direction of the field. At what frequency does the electron traverse a circular path? (mel = 9.11 × 10^-31 kg, e = 1.60 × 10^-19 C) A) 2.1 × 10^10 Hz B) 4.8 × 10^-7 Hz C) 2.1 × 10^14 Hz D) 4.8 × 10^-11 Hz
A) 2.1 × 10^10 Hz
What is the minimum magnitude of an electric field that balances the weight of a plastic sphere of mass that has been charged to -3.0 nC? A) 2.1 × 10^7 N/C B) 2.4 × 10^6 N/C C) 4.5 × 10^6 N/C D) 6.4 × 10^6 N/C
A) 2.1 × 10^7 N/C
A tiny object carrying a charge of +3.00 μC and a second tiny charged object are initially very far apart. If it takes 29.0 J of work to bring them to a final configuration in which the +3.00 μC object i is at x = 1.00 mm, y = 1.00 mm, and the other charged object is at x = 1.00 mm, y = 3.00 mm, find the magnitude of the charge on the second object. (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 2.15 μC B) 4.30 μC C) 10.74 μC D) 4.30 nC
A) 2.15 μC
An electron moving perpendicular to a uniform magnetic field of 3.2 × 10^-2 T moves in a circle of radius 0.40 cm. How fast is this electron moving? (mel = 9.11 × 10^-31 kg. e = 1.60 × 10^-19 C) A) 2.2 × 10^7 m/s B) 1.9 × 10^-2 m/s C) 1.9 × 10^-30 m/s D) 3.0 × 10^6 m/s E) 8.0 × 10^6 m/s
A) 2.2 × 10^7 m/s
An LRC series circuit has voltage supplied to it at a frequency of 13.0 kHz with a phase difference between the current and the voltage of magnitude 0.20 rad. If the circuit has a capacitance of 5.0 μF and an inductance of 0.050 H find the resistance of the circuit. A) 20 kΩ B) 0.99 kΩ C) 9.0 kΩ D) 0.32 kΩ
A) 20 kΩ
A 120-V rms voltage at 60.0 Hz is applied across an inductor, a capacitor, and a resistor in series. If the peak current in this circuit is 0.8484 A, what is the impedance of this circuit? A) 200 Ω B) 141 Ω C) 20.4 Ω D) 120 Ω E) 100 Ω
A) 200 Ω
Two point charges of +20.0 μC and -8.00 μC are separated by a distance of 20.0 cm. What is the magnitude of electric field due to these charges at a point midway between them? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 25.2 × 10^6 N/C directed toward the negative charge B) 25.2 × 10^6 N/C directed toward the positive charge C) 25.2 × 10^5 N/C directed toward the negative charge D) 25.2 × 10^5 N/C directed toward the positive charge E) 25.2 × 10^4 N/C directed toward the negative charge
A) 25.2 × 10^6 N/C directed toward the negative charge
The electric field strength in the space between two closely spaced parallel disks is 1.0 × 105 N/C. This field is the result of transferring 3.9 × 109 electrons from one disk to the other. What is the diameter of the disks? (e = 1.60 × 10^-19 C, ε0 = 8.85 × 10^-12 C2/N · m2) A) 3.0 cm B) 1.5 cm C) 4.5 cm D) 6.0 cm
A) 3.0 cm
The capacitance per unit length of a very long coaxial cable, made of two concentric cylinders, is 50 pF/m. What is the radius of the outer cylinder if the radius of the inner one is 1.0 mm? (k = 1/4πε0 = 8.99 × 10^9 N · m^2/C^2) A) 3.0 mm B) 2.0 mm C) 4.0 mm D) 1.0 mm E) 0.50 mm
A) 3.0 mm
A series LRC circuit has a sinusoidal voltage supplied to it at 197 kHz with a peak voltage of 270 V, a 41-kΩ resistance, a 14-μF capacitor, and a 63-H inductance. What is the peak current for this circuit? A) 3.5 μA B) 2.3 μA C) 4.2 μA D) 6.6 μA
A) 3.5 μA
Two flat 4.0 cm × 4.0 cm electrodes carrying equal but opposite charges are spaced 2.0 mm apart with their midpoints opposite each other. Between the electrodes but not near their edges, the electric field strength is 2.5 × 106 N/C. What is the magnitude of the charge on each electrode? (ε0 = 8.85 × 10^-12 C2/N · m2) A) 35 nC B) 18 nC C) 16 nC D) 30 nC
A) 35 nC
Each plate of a parallel-plate air-filled capacitor has an area of 0.0020 m2, and the separation of the plates is 0.020 mm. An electric field of 3.9 × 106 V/m is present between the plates. What is the surface charge density on the plates? (ε0 = 8.85 × 10^-12 C2^/N · m^2) A) 35 μC/m^2 B) 73 μC/m^2 C) 17 μC/m^2 D) 52 μC/m^2 E) 87 μC/m^2
A) 35 μC/m^2
A 1.0 m long piece of coaxial cable has a wire with a radius of 1.1 mm and a concentric conductor with inner radius 1.3 mm. The area between the cable and the conductor is filled with a dielectric. If the voltage drop across the capacitor is 6000 V when the line charge density is 8.8 μC/m, find the value of the dielectric constant. (k=1/4πε0 =8.99×10^9 N·m^2/C^2) A) 4.4 B) 4.8 C) 5.3 D) 5.7
A) 4.4
A ‐3.0-μC point charge and a ‐9.0-μC point charge are initially extremely far apart. How much work does it take to bring the ‐3.0-μC charge to x = 3.0 mm, y = 0.00 mm and the ‐9.0-μC charge to x = ‐3.0 mm, y = 0.00 mm?(k=1/4πε0 =8.99×10^9N·m2/C2) A) 40 J B) 81 J C) 27 J D) 6.8 J
A) 40 J
A laser with a power of 1.0 mW has a beam radius of 1.0 mm. What is the peak value of the electric field in that beam? (c = 3.0 x 10^8 m/s, μ0 = 4π × 10^-7 T · m/A, ε0 = 8.85 × 10^-12 C^2/N · m^2) A) 490 V/m B) 840 V/m C) 65 V/m D) 120 V/m E) 22 V/m
A) 490 V/m
A series circuit has a resistance of 4.0 Ω, a reactance (due to the capacitance) of 21.0 Ω, and a reactance (due to the inductance) of 17.0 Ω. Find the impedance of the circuit. A) 5.7 Ω B) 27 Ω C) 8.0 Ω D) 42 Ω
A) 5.7 Ω
If an electron is accelerated from rest through a potential difference of 9.9 kV, what is its resulting speed? (e = 1.60×10^-19C, k=1/4πε0 = 8.99×10^9N·m2/C2, mel=9.11x10^-31kg) A) 5.9 × 10^7 m/s B) 4.9 × 10^7 m/s C) 3.9 × 10^7 m/s D) 2.9 × 10^7 m/s
A) 5.9 × 10^7 m/s
A conducting sphere is charged up such that the potential on its surface is 100 V (relative to infinity). If the sphereʹs radius were twice as large, but the charge on the sphere were the same, what would be the potential on the surface relative to infinity? A) 50 V B) 25 V C) 100 V D) 200 V
A) 50 V
A series circuit consists of a 50-Hz ac source, a 50-Ω resistor, a 0.50-H inductor, and a 60-μF capacitor. The rms current in the circuit is measured to be 3.1 A. What is the voltage amplitude of the source? A) 510 V B) 270 V C) 220 V D) 180 V E) 160 V
A) 510 V
Two square air-filled parallel plates that are initially uncharged are separated by 1.2 mm, and each of them has an area of 190 mm2. How much charge must be transferred from one plate to the other if 1.1 nJ of energy are to be stored in the plates? (ε00 = 8.85 × 10^-12 C^2/N · m^2) A) 56 pC B) 39 pC C) 78 pC D) 3.5 μC
A) 56 pC
The magnitude of the magnetic field at point P for a certain electromagnetic wave is 2.12 μT. What is the magnitude of the electric field for that wave at P? (c = 3.0 x 10^8 m/s) A) 636 N/C B) 745 N/C C) 5.23 μN/C D) 6.36 μN/C E) 7.45 μN/C
A) 636 N/C
A very long thin wire produces a magnetic field of 0.0050 × 10^-4 T at a distance of 3.0 mm. from the central axis of the wire. What is the magnitude of the current in the wire? (μ0 = 4π × 10^-7 T · m/A) A) 7.5 mA B) 1.7 mA C) 3300 mA D) 24,000 mA
A) 7.5 mA
A very long wire carries a uniform linear charge density of 7.0 nC/m. What is the electric field strength 16.0 m from the center of the wire at a point on the wireʹs perpendicular bisector? (ε0 = 8.85 × 10^-12 C2/N · m2) A) 7.9 N/C B) 3.9 N/C C) 0.49 N/C D) 0.031 N/C
A) 7.9 N/C
An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of 48 mm and 84 mm. The electric potential of the inner conductor with respect to the outer conductor is -400 V. (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) The energy stored in a 1.0-m length of this capacitor is closest to A) 8.0 μJ. B) 5.7 μJ. C) 11 μJ. D) 16 μJ. E) 22 μJ.
A) 8.0 μJ.
A ‐7.0-μC point charge has a positively charged object in an elliptical orbit around it. If the mass of the positively charged object is 1.0 kg and the distance varies from 5.0 mm to 20.0 mm between the charges, what is the maximum electric potential difference through which the positive object moves? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 9.4 MV B) 3.2 MV C) 4.2 MV D) 16 MV
A) 9.4 MV
A cylindrical capacitor is made of two thin-walled concentric cylinders. The inner cylinder has radius r1 = 4.0 mm, and the outer one a radius r2= 8.0 mm. The common length of the cylinders is L = 150 m. What is the potential energy stored in this capacitor when a potential difference 4.0 V is applied between the inner and outer cylinder? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 9.6 × 10^-8 J B) 1.3 × 10^-8 J C) 6.3 × 10^-8 J D) 0.34 × 10^-8 J E) 4.6 × 10^-8 J
A) 9.6 × 10^-8 J
A series ac circuit consists of an inductor having a reactance of 80 Ω and an inductance of 190 mH, a 40 -Ω resistor, a capacitor whose reactance is 100 Ω, and an ac source. The rms current in the circuit is measured to be 2.2 A. What is the rms voltage of the source? A) 98 V B) 96 V C) 93 V D) 91 V E) 88 V
A) 98 V
Two point charges Q1 and Q2 of equal magnitudes and opposite signs are positioned as shown in the figure. Which of the arrows best represents the net electric field at point P due to these two charges? A) A B) B C) C D) D E) The field is equal to zero at point P.
A) A
Which statements are true for an electron moving in the direction of an electric field? (There may be more than one correct choice.) A) Its electric potential energy increases as it goes from high to low potential. B) Its electric potential energy decreases as it goes from high to low potential. C) Its potential energy increases as its kinetic energy decreases. D) Its kinetic energy decreases as it moves in the direction of the electric field. E) Its kinetic energy increases as it moves in the direction of the electric field.
A) Its electric potential energy increases as it goes from high to low potential. D) Its kinetic energy decreases as it moves in the direction of the electric field. E) Its kinetic energy increases as it moves in the direction of the electric field.
Two capacitors, C1 and C2, are connected in series across a source of potential difference. With the potential source still connected, a dielectric is now inserted between the plates of capacitor C1. What happens to the charge on capacitor C2? A) The charge on C2 increases. B) The charge on C2 decreases. C) The charge on C2 remains the same.
A) The charge on C2 increases.
Equal but opposite charges Q are placed on the square plates of an air‐filled parallel‐plate capacitor. The plates are then pulled apart to twice their original separation, which is small compared to the dimensions of the plates. Which of the following statements about this capacitor are true? (There may be more than one correct choice.) A) The energy stored in the capacitor has doubled. B) The energy density in the capacitor has increased. C) The electric field between the plates has increased. D) The potential difference across the plates has doubled. E) The capacitance has doubled.
A) The energy stored in the capacitor has doubled. D) The potential difference across the plates has doubled.
A nonconducting sphere contains positive charge distributed uniformly throughout its volume. Which statements about the potential due to this sphere are true? All potentials are measured relative to infinity. (There may be more than one correct choice.) A) The potential is highest at the center of the sphere. B) The potential at the center of the sphere is zero. C) The potential at the center of the sphere is the same as the potential at the surface. D) The potential at the surface is higher than the potential at the center. E) The potential at the center is the same as the potential at infinity.
A) The potential is highest at the center of the sphere.
If the electrical potential in a region is constant, the electric field must be zero everywhere in that region. A) True B) False
A) True
When the electric field is zero at a point, the potential must also be zero there. A) True B) False
A) True
The energy per unit volume in an electromagnetic wave is ________. A) equally divided between the electric and magnetic fields. B) mostly in the electric field. C) mostly in the magnetic field. D) all in the electric field. E) all in the magnetic field.
A) equally divided between the electric and magnetic fields.
A charged particle is moving with speed v perpendicular to a uniform magnetic field. A second identical charged particle is moving with speed 2v perpendicular to the same magnetic field. If the frequency of revolution of the first particle is f, the frequency of revolution of the second particle is _______. A) f. B) 2f. C) 4f. D) f/2. E) f/4.
A) f.
An electromagnetic wave is propagating towards the west. At a certain moment the direction of the magnetic field vector associated with this wave points vertically up. The direction of the electric field vector of this wave is ___________. A) horizontal and pointing south. B) vertical and pointing down. C) horizontal and pointing north. D) vertical and pointing up. E) horizontal and pointing east.
A) horizontal and pointing south.
Suppose you have two point charges of opposite sign. As you move them farther and farther apart, the potential energy of this system relative to infinity A) increases. B) decreases. C) stays the same.
A) increases.
Consider a solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire. If the radius of the solenoid were doubled (becoming 2b), and all other quantities remained the same, the magnetic field inside the solenoid would _______. A) remain the same. B) become twice as strong. C) become one half as strong.
A) remain the same.
When two or more capacitors are connected in parallel across a potential difference A) the potential difference across each capacitor is the same. B) each capacitor carries the same amount of charge. C) the equivalent capacitance of the combination is less than the capacitance of any of the capacitors. D) All of the above choices are correct. E) None of the above choices are correct.
A) the potential difference across each capacitor is the same.
An electron, moving toward the west, enters a uniform magnetic field. Because of this field the electron curves upward. The direction of the magnetic field is ________. A) towards the north. B) towards the south. C) towards the west. D) upward. E) downward.
A) towards the north.
A 3.0-μC positive point charge is located at the origin and a 2.0 μC positive point charge is located at x = 0.00 m, y = 1.0 m. Find the coordinates of the point where the net electric field strength due to these charges is zero. A) x = 0.00 m, y = 0.55 m B)x=0.00 m,y=0.67m C)x=0.00 m,y=1.5m D)x=0.00 m,y=0.60m
A) x = 0.00 m, y = 0.55 m
In the figure, a ring 0.71 m in radius carries a charge of + 580 nC uniformly distributed over it. A point charge Q is placed at the center of the ring. The electric field is equal to zero at field point P, which is on the axis of the ring, and 0.73 m from its center. (ε0 = 8.85 × 10^-12 C2/N · m2) The point charge Q is closest to A) ‐210 B) ‐300 C) ‐420 D) 210 E) 300
A) ‐210
Two point charges of +1.0 μC and ‐2.0 μC are located 0.50 m apart. What is the minimum amount of work needed to move the charges apart to double the distance between them? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) ‐36 mJ B) +18 mJ C) 0 mJ D) +36 mJ E) ‐18 mJ
B) +18 mJ
If an electromagnetic wave has components Ey = E0 sin(kx - ωt) and Bz = B0 sin(kx - ωt) , in what direction is it traveling? A) -x B) +x C) +y D) -y E) +z
B) +x
An electron moving in the direction of the +x‐axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, the direction of the magnetic field in this region points in the direction of the ________. A) +z‐axis. B) -z‐axis. C) -x‐axis. D) +y‐axis. E) -y‐axis.
B) -z‐axis.
A proton starting from rest travels through a potential of 1.0 kV and then moves into a uniform 0.040 -T magnetic field. What is the radius of the protonʹs resulting orbit? (m of proton = 1.67 × 10^-27 kg, e = 1.60 × 10^-19 C) A) 0.080 m B) 0.11 m C) 0.14 m D) 0.17 m E) 0.19 m
B) 0.11 m
The inductor in a radio receiver carries a current of amplitude 200 mA when a voltage of amplitude 2.40 V is across it at a frequency of 1400 kHz. What is the value of the inductance? A) 1.43 μH B) 1.36 μH C) 9.20 μH D) 4.42 μH E) 1.97 μH
B) 1.36 μH
The magnitude of the electric field at a point P for a certain electromagnetic wave is 570 N/C. What is the magnitude of the magnetic field for that wave at P? (c = 3.0 x 10^8 m/s) A) 2.91 μT B) 1.90 μT C) 1.10 μT D) 1.41 μT E) 2.41 μT
B) 1.90 μT
An electron is released from rest at a distance of 9.00 cm from a proton. If the proton is held in place, how fast will the electron be moving when it is 3.00 cm from the proton? (mel = 9.11 x 10^-31 kg, e = 1.60 × 10^-19 C, k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 75.0 m/s B) 106 m/s C) 130 m/s D) 1.06 × 10^3 m/s E) 4.64 × 10^5 m/s
B) 106 m/s
The phase angle of an LRC series circuit with an inductive reactance of 200 Ω and a capacitive reactance of 100 Ω is 40.0°. What is the value of the resistor in this circuit? A) 100 Ω B) 119 Ω C) 156 Ω D) 200 Ω E) 265 Ω
B) 119 Ω
A 25.0-mH inductor, a 2.00-μF capacitor, and a certain resistor are connected in series across an ac voltage source at 1000 Hz. If the impedance of this circuit is 200 Ω, what is the resistance of the resistor? A) 100 Ω B) 184 Ω C) 200 Ω D) 552 Ω E) 579 Ω
B) 184 Ω
At what distance from the central axis of a long straight thin wire carrying a current of 5.0 A is the magnitude of the magnetic field due to the wire equal to the strength of the Earthʹs magnetic field of about 5.0 × 10^-5 T? ( μ0 = 4π × 10^-7 T · m/A) A) 1.0 cm B) 2.0 cm C) 3.0 cm D) 4.0 cm E) 5.0 cm
B) 2.0 cm
An ideal air‐filled parallel‐plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates. All the geometric parameters of the capacitor (plate diameter and plate separation) are now DOUBLED. If the original capacitance was C0, what is the new capacitance? A) 4C0 B) 2C0 C) C0 D) C0/2 E) C0/4
B) 2C0
An ideal parallel‐plate capacitor consists of a set of two parallel plates of area A separated by a very small distance d. When the capacitor plates carry charges +Q and -Q, the capacitor stores energy U0. If the separation between the plates is doubled, how much electrical energy is stored in the capacitor? A) 4U0 B) 2U0 C) U0 D) U0/2 E) U0/4
B) 2U0
One very small uniformly charged plastic ball is located directly above another such charge in a test tube as shown in the figure. The balls are in equilibrium a distance d apart. If the charge on each ball is doubled, the distance between the balls in the test tube would become A) √2d. B) 2d. C) 4d. D) 8d.
B) 2d.
A straight wire that is 0.60 m long is carrying a current of 2.0 A. It is placed in a uniform magnetic field of strength 0.30 T. If the wire experiences a force of 0.18 N, what angle does the wire make with respect to the magnetic field? A) 25° B) 30° C) 35° D) 60° E) 90°
B) 30°
A 120-V rms voltage at 1000 Hz is applied to an inductor, a 2.00-μF capacitor and a 100-Ω resistor, all in series. If the rms value of the current in this circuit is 0.680 A, what is the inductance of the inductor? A) 34.2 mH B) 35.8 mH C) 11.4 mH D) 17.9 mH E) 22.8 mH
B) 35.8 mH
In a mass spectrometer, a singly-charged particle (charge e) has a speed of 1.0 × 10^6 m/s and enters a uniform magnetic field of 0.20 T. The radius of the circular orbit of the particle is 0.020 m. What is the mass of this particle? (e = 1.60 × 10^-19 C) A) 3.2 × 10^-28 kg B) 6.4 × 10^-28 kg C) 1.7 × 10^-27 kg D) 4.5 × 10^-27 kg E) 3.1 × 10^-31 kg
B) 6.4 × 10^-28 kg
Given that the wavelengths of visible light range from 400 nm to 700 nm, what is the highest frequency of visible light? (c = 3.0 x 10^8 m/s) A) 3.1 × 10^8 Hz B) 7.5 × 10^14 Hz C) 2.3 × 10^20 Hz D) 4.3 × 10^14 Hz E) 5.0 × 10^8 Hz
B) 7.5 × 10^14 Hz
A metal sphere of radius 10 cm carries a charge of +2.0 μC uniformly distributed over its surface. What is the magnitude of the electric field due to this sphere at a point 5.0 cm outside the sphereʹs surface? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) 4.0 × 10^5 N/C B) 8.0 × 10^5 N/C C) 4.2 × 10^6 N/C D) 4.0 × 10^7 N/C E) 8.0 × 10^7 N/C
B) 8.0 × 10^5 N/C
Two cables of the same length are made of the same material, except that one cable has twice the diameter of the other cable. When the same potential difference is maintained across both cables, which of the following statements are true? (There may be more than one correct choice.) A) The same current flows through both cables. B) Both cables carry the same current density. C) The electrons have the same drift velocity in both cables. D) The current in the thin cable is twice as great as the current in the thick cable. E) The current in the thin cable is four times as great as the current in the thick cable.
B) Both cables carry the same current density. C) The electrons have the same drift velocity in both cables.
As current flows through a uniform wire, the wire gets hotter because the electrons stop moving and therefore transform their lost kinetic energy into thermal energy in the wire. A) True B) False
B) False
If the electric field is zero everywhere inside a region of space, the potential must also be zero in that region. A) True B) False
B) False
If the electric potential at a point in space is zero, then the electric field at that point must also be zero. A) True B) False
B) False
Two equal positive charges are held in place at a fixed distance. If you put a third positive charge midway between these two charges, its electrical potential energy of the system (relative to infinity) is zero because the electrical forces on the third charge due to the two fixed charges just balance each other. A) True B) False
B) False
In the circuit shown in the figure, the capacitors are initially uncharged. The switch is first thrown to position A and kept there for a long time. It is then thrown to position B. Let the charges on the capacitors be Q1, Q2, and Q3 and the potential differences across them be V1, V2, and V3. Which of the following conditions must be true with the switch in position B? A) V1 = V2 = V3 B) V1 + V2 = V3 C) V3 = V0 D) Q1 = Q2 = Q3 E) Q1 + Q2 = Q3
B) V1 + V2 = V3
Suppose you have two negative point charges. As you move them farther and farther apart, the potential energy of this system relative to infinity A) increases. B) decreases. C) stays the same.
B) decreases.
A negative charge, if free, will tend to move A) from high potential to low potential. B) from low potential to high potential. C) toward infinity. D) away from infinity. E) in the direction of the electric field.
B) from low potential to high potential.
The figure shows two unequal point charges, q and Q, of opposite sign. Charge Q has greater magnitude than charge q. In which of the regions X, Y, Z will there be a point at which the net electric field due to these two charges is zero? A) only regions X and Z B) only region X C) only region Y D) only region Z E) all three regions
B) only region X
Two long parallel wires placed side‐by‐side on a horizontal table carry identical size currents in opposite directions. The wire on your right carries current toward you, and the wire on your left carries current away from you. From your point of view, the magnetic field at the point exactly midway between the two wires ________. A) points upward. B) points downward. C) points toward you. D) points away from you. E) is zero.
B) points downward.
If the magnetic field of an electromagnetic wave is in the +x‐direction and the electric field of the wave is in the +y‐direction, the wave is traveling in the __________. A) xy‐plane. B) +z‐direction. C) -z‐direction. D) -x‐direction. E) -y‐direction.
C) -z‐direction.
Four equal negative point charges are located at the corners of a square, their positions in the xy‐plane being (1, 1), (‐1, 1), (‐1, ‐1), (1, ‐1). The electric field on the x‐axis at (1, 0) points in the same direction as A) ˆj B) î C) -î D) ˆk E) -ˆj
C) -î
Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude F due to the other. With time, charge gradually leaks off of both spheres. When each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be A) 1/16 F. B) 1/8 F. C) 1/4 F. D) 1/2 F.
C) 1/4 F.
A charge of 2.00 μC flows onto the plates of a capacitor when it is connected to a 12.0 -V potential source. What is the minimum amount of work that must be done in charging this capacitor? A) 6.00 μJ B) 24.0 μJ C) 12.0 μJ D) 144 μJ E) 576 μJ
C) 12.0 μJ
The magnetic field at a distance of 2 cm from a current carrying wire is 4 μT. What is the magnetic field at a distance of 4 cm from the wire? A) 1/2 μT B) 1 μT C) 2 μT D) 4 μT E) 8 μT
C) 2 μT
An ac source having a maximum voltage output of 30 V is connected in series with a 50 -Ω resistor, a 0.60-H inductor, and a 20-μF capacitor. What is the maximum charge on the capacitor when the frequency of the source is adjusted so that the circuit is in resonance? A) 1.0 mC B) 0.00 mC C) 2.1 mC D) 4.2 mC E) 8.4 mC
C) 2.1 mC
A thin, circular disk of radius 30.0 cm is oriented in the yz-plane with its center at the origin. The disk carries a total charge of +3.00 μC distributed uniformly over its surface. Calculate the magnitude of the electric field due to the disk at the point x = 15.0 cm along the x-axis. (ε0 = 8.85 × 10^-12 C2/N · m2) A) 9.95 × 10^5 N/C B) 4.98 × 10^5 N/C C) 3.31 × 10^5 N/C D) 2.49 × 10^5 N/C E) 1.99 × 10^5 N/C
C) 3.31 × 10^5 N/C
A thin copper rod that is 1.0 m long and has a mass of 0.050 kg is in a magnetic field of 0.10 T. What minimum current in the rod is needed in order for the magnetic force to cancel the weight of the rod? A) 1.2 A B) 2.5 A C) 4.9 A D) 7.6 A E) 9.8 A
C) 4.9 A
An atomic nucleus has a charge of +40e. What is the magnitude of the electric field at a distance of 1.0 m from the center of the nucleus? (k = 1/4πε0 = 8.99 × 109 N · m2/C2, e = 1.60 × 10^-19 C) A) 5.4 × 10^-8 N/C B) 5.6 × 10^-8 N/C C) 5.8 × 10^-8 N/C D) 6.0 × 10^-8 N/C E) 6.2 × 10^-8 N/C
C) 5.8 × 10^-8 N/C
A beam of electrons is accelerated through a potential difference of 10 kV before entering a region having uniform electric and magnetic fields that are perpendicular to each other and perpendicular to the direction in which the electron is moving. If the magnetic field in this region has a value of 0.010 T, what magnitude of the electric field is required if the particles are to be undeflected as they pass through the region? A) 2.3 × 10^3 V/m B) 7.9 × 10^3 V/m C) 5.9 × 10^5 V/m D) 6.0 × 10^5 V/m E) 7.2 × 10^6 V/m
C) 5.9 × 10^5 V/m
A parallel-plate capacitor has a capacitance of 10 mF and charged with a 20 -V power supply. The power supply is then removed and a dielectric material of dielectric constant 4.0 is used to fill the space between the plates. How much energy is now stored by the capacitor? A) 250 mJ B) 125 mJ C) 500 mJ D) 62.5 mJ E) 1200 mJ
C) 500 mJ
Two long parallel wires carry currents of 10 A in opposite directions. They are separated by 40 cm. What is the magnitude of the magnetic field in the plane of the wires at a point that is 20 cm from one wire and 60 cm from the other? (μ0 = 4π × 10^-7 T · m/A) A) 1.5 μT B) 3.3 μT C) 6.7 μT D) 33 μT E) 67 μT
C) 6.7 μT
A proton is placed in an electric field of intensity 700 N/C. What are the magnitude and direction of the acceleration of this proton due to this field? (mproton = 1.67 × 10^-27 kg, e = 1.60 × 10^-19 C) A) 6.71 × 10^9 m/s2 opposite to the electric field B) 6.71 × 10^10 m/s2 opposite to the electric field C) 6.71 × 10^10 m/s2 in the direction of the electric field D) 67.1 × 10^10 m/s2 opposite to the electric field E) 67.1 × 10^10 m/s2 in the direction of the electric field
C) 6.71 × 10^10 m/s2 in the direction of the electric field
Three equal negative point charges are placed at three of the corners of a square of side d as shown in the figure. Which of the arrows represents the direction of the net electric field at the center of the square? A) A B) B C) C D) D E) The field is equal to zero at point P.
C) C
Two large, flat, horizontally oriented plates are parallel to each other, a distance d apart. Half way between the two plates the electric field has magnitude E. If the separation of the plates is reduced to d/2 what is the magnitude of the electric field half way between the plates? A) 4E B) 2E C) E D) 0 E) E/2
C) E
A point charge Q is located a short distance from a point charge 3Q, and no other charges are present. If the electrical force on Q is F, what is the electrical force on 3Q? A) F/3 B)F/ 3 C) F D) 3F E) 3F
C) F
Two very large parallel sheets a distance d apart have their centers directly opposite each other. The sheets carry equal but opposite uniform surface charge densities. A point charge that is placed near the middle of the sheets a distance d/2 from each of them feels an electrical force F due to the sheets. If this charge is now moved closer to one of the sheets so that it is a distance d/4 from that sheet, what force will feel? A) 4F B) 2F C) F D) F/2 E) F/4
C) F
A negative charge is moved from point A to point B along an equipotential surface. Which of the following statements must be true for this case? A) The negative charge performs work in moving from point A to point B. B) Work is required to move the negative charge from point A to point B. C) No work is required to move the negative charge from point A to point B. D) The work done on the charge depends on the distance between A and B. E) Work is done in moving the negative charge from point A to point B.
C) No work is required to move the negative charge from point A to point B.
When an LRC series circuit is driven at resonance, which of the following statements about the circuit are correct? (There may be more than one correct choice.) A) The impedance of the circuit is zero. B) The impedance of the circuit has its maximum value. C) The impedance of the circuit has its minimum value. D) The inductive reactance and the capacitive reactance are both zero. E) The inductive reactance and the capacitive reactance are exactly equal to each other.
C) The impedance of the circuit has its minimum value. E) The inductive reactance and the capacitive reactance are exactly equal to each other.
Suppose a region of space has a uniform electric field, directed towards the right, as shown in the figure. Which statement about the electric potential is true? A) The potential at all three locations (A, B, C) is the same because the field is uniform. B) The potential at points A and B are equal, and the potential at point C is higher than the potential at point A. C) The potential at points A and B are equal, and the potential at point C is lower than the potential at point A. D) The potential at point A is the highest, the potential at point B is the second highest, and the potential at point C is the lowest.
C) The potential at points A and B are equal, and the potential at point C is lower than the potential at point
A conducting sphere contains positive charge distributed uniformly over its surface. Which statements about the potential due to this sphere are true? All potentials are measured relative to infinity. (There may be more than one correct choice.) A) The potential is lowest, but not zero, at the center of the sphere. B) The potential at the center of the sphere is zero. C) The potential at the center of the sphere is the same as the potential at the surface. D) The potential at the surface is higher than the potential at the center. E) The potential at the center is the same as the potential at infinity.
C) The potential at the center of the sphere is the same as the potential at the surface.
An ac source of period T and maximum voltage V is connected to a single unknown ideal element that is either a resistor, and inductor, or a capacitor. At time t = 0 the voltage is zero. At time t = T/4 the current in the unknown element is equal to zero, and at time t = T/2 the current is I = ‐Imax, where Imax is the current amplitude. What is the unknown element? A) a resistor B) an inductor C) a capacitor D) an inductor or a capacitor
C) a capacitor
Consider a solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire. If the length of the solenoid became twice as long ( 2L), and all other quantities remained the same, the magnetic field inside the solenoid would _______. A) remain the same. B) become twice as strong. C) become one half as strong.
C) become one half as strong.
In an electromagnetic wave, the electric and magnetic fields are oriented such that they are _________. A) parallel to one another and perpendicular to the direction of wave propagation. B) parallel to one another and parallel to the direction of wave propagation. C) perpendicular to one another and perpendicular to the direction of wave propagation. D) perpendicular to one another and parallel to the direction of wave propagation.
C) perpendicular to one another and perpendicular to the direction of wave propagation.
An air‐filled parallel‐plate capacitor is connected to a battery and allowed to charge up. Now a slab of dielectric material is placed between the plates of the capacitor while the capacitor is still connected to the battery. After this is done, we find that A) the energy stored in the capacitor had decreased. B) the voltage across the capacitor had increased. C) the charge on the capacitor had increased. D) the charge on the capacitor had not changed. E) None of these choices are true.
C) the charge on the capacitor had increased.
A horizontal wire carries a current straight toward you. From your point of view, the magnetic field at a point directly below the wire points _________. A) directly away from you. B) to the left. C) to the right. D) directly toward you. E) vertically upward.
C) to the right.
When two point charges are a distance d part, the electric force that each one feels from the other has magnitude F. In order to make this force twice as strong, the distance would have to be changed to A) 2d. B) 2d. C)d/ 2 D) d/2. E) d/4.
C)d/ 2
A charge is accelerated from rest through a potential difference V and then enters a uniform magnetic field oriented perpendicular to its path. The field deflects the particle into a circular arc of radius R. If the accelerating potential is tripled to 3V, what will be the radius of the circular arc? A) 9R B) 3R C) √3R D)R/√3 E) R/9
C)√3R
A long, thin rod parallel to the y-axis is located at x = ‐1.0 cm and carries a uniform linear charge density of +1.0 nC/m. A second long, thin rod parallel to the z-axis is located at x = +1.0 cm and carries a uniform linear charge density of ‐1.0 nC/m. What is the net electric field due to these rods at the origin? ( ε0 = 8.85 × 10^-12 C2/N · m2) A) (‐3.6 × 10^3 N/C) î B) (1.8 × 10^3 N/C) j C) (‐1.8 × 10^3 N/C) k D) (3.6 × 10^3 N/C) î E) zero
D) (3.6 × 10^3 N/C) î
A +7.00 μC point charge and -9.00 μC point charge are placed along the x-axis at x = 0.000 cm and x = 40.0 cm, respectively. Where must a third charge, q, be placed along the x-axis so that it does not experience any net electric force due to the other two charges? A) -0.200 m B) 2.99 m C) -0.187 m D) -2.99 m E) 0.187 m
D) -2.99 m
A 6.00-μF parallel-plate capacitor has charges of ±40.0 μC on its plates. How much potential energy is stored in this capacitor? A) 103 μJ B) 113 μJ C) 123 μJ D) 133 μJ E) 143 μJ
D) 133 μJ
A wire of resistivity ρ must be replaced in a circuit by a wire of the same material but 4 times as long. If, however, the resistance of the new wire is to be the same as the resistance of the original wire, the diameter of the new wire must be __________. A) the same as the diameter of the original wire. B) 1/2 the diameter of the original wire. C) 1/4 the diameter of the original wire. D) 2 times the diameter of the original wire. E) 4 times the diameter of the original wire.
D) 2 times the diameter of the original wire.
A 6.0-μF air-filled capacitor is connected across a 100-V voltage source. After the source fully charges the capacitor, the capacitor is immersed in transformer oil (of dielectric constant 4.5). How much ADDITIONAL charge flows from the voltage source, which remained connected during the process? A) 1.2 mC B) 1.5 mC C) 1.7 mC D) 2.1 mC E) 2.5 mC
D) 2.1 mC
Two identical small conducting spheres are separated by 0.60 m. The spheres carry different amounts of charge and each sphere experiences an attractive electric force of 10.8N. The total charge on the two spheres is ‐24 μC. The two spheres are now connected by a slender conducting wire, which is then removed. The electric force on each sphere is closest to A) zero. B) 3.6 N, attractive. C) 5.4 N, attractive. D) 3.6 N, repulsive. E) 5.4 N, repulsive.
D) 3.6 N, repulsive.
A metal cylinder of radius 2.0 mm is concentric with another metal cylinder of radius 5.0 mm. If the space between the cylinders is filled with air and the length of the cylinders is 50 cm, what is the capacitance of this arrangement? (k = 1/4πε0 = 8.99 × 10^9 N · m^2/C^2) A) 33 pF B) 60 pF C) 22 pF D) 30 pF E) 11 pF
D) 30 pF
The phase angle of an LRC series circuit with an inductive reactance of 200 Ω, a resistor of 200 Ω and a certain capacitor at 1000 Hz is 40.0°. What is the value of the capacitance in this circuit? A) 1.95 μF B) 2.95 μF C) 3.95 μF D) 4.95 μF E) 5.95 μF
D) 4.95 μF
A parallel-plate capacitor has a capacitance of 10 mF and is charged with a 20-V power supply. The power supply is then removed and a dielectric material of dielectric constant 4.0 is used to fill the space between the plates. What is the voltage now across the capacitor? A) 80 V B) 20 V C) 10 V D) 5.0 V E) 2.5 V
D) 5.0 V
The y component of the electric field of an electromagnetic wave traveling in the +x direction through vacuum obeys the equation Ey = (375 N/C) cos[kx - (2.20 × 10^14 rad/s)t]. What is the wavelength of this electromagnetic wave? (c = 3.0 x 10^8 m/s) A) 0.272 μm B) 1.36 μm C) 2.72 μm D) 8.57 μm E) 17.1 μm
D) 8.57 μm
When two or more capacitors are connected in series across a potential difference A) the potential difference across the combination is the algebraic sum of the potential differences across the individual capacitors. B) each capacitor carries the same amount of charge. C) the equivalent capacitance of the combination is less than the capacitance of any of the capacitors. D) All of the above choices are correct. E) None of the above choices are correct.
D) All of the above choices are correct.
The electric field between square the plates of a parallel‐plate capacitor has magnitude E. The potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. The magnitude of the electric field between the plates is now equal to A) 4E. B) 2E. C) E. D) E/2. E) E/4.
D) E/2.
When an electromagnetic wave falls on a white, perfectly reflecting surface, it exerts a force F on that surface. If the surface is now painted a perfectly absorbing black, what will be the force that the same wave will exert on the surface? A) 4F B) 2F C) F D) F/2 E) F/4
D) F/2
The charge on the square plates of a parallel‐plate capacitor is Q. The potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. The amount of charge on the plates is now equal to A) 4Q. B) 2Q. C) Q. D) Q/2. E) Q/4.
D) Q/2.
A charged capacitor stores energy U. Without connecting this capacitor to anything, dielectric having dielectric constant K is now inserted between the plates of the capacitor, completely filling the space between them. How much energy does the capacitor now store? A) 2KU B) KU C) U D) U/K E) U/2K
D) U/K
An ideal air‐filled parallel‐plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates. All the geometric parameters of the capacitor (plate diameter and plate separation) are now DOUBLED. If the original energy stored in the capacitor was U0, how much energy does it now store? A) 4U0 B) 2U0 C) U0 D) U0/2 E) U0/4
D) U0/2
An ideal parallel‐plate capacitor consists of a set of two parallel plates of area A separated by a very small distance d. When this capacitor is connected to a battery that maintains a constant potential difference between the plates, the energy stored in the capacitor is U0. If the separation between the plates is doubled, how much energy is stored in the capacitor? A) 4U0 B) 2U0 C) U0 D) U0/2 E) U0/4
D) U0/2
X and Y are two uncharged metal spheres on insulating stands, and are in contact with each other. A positively charged rod R is brought close to X as shown in Figure (a). Sphere Y is now moved away from X, as in Figure (b). What are the final charge states of X and Y? A) Both X and Y are neutral. B) X is positive and Y is neutral. C) X is neutral and Y is positive. D) X is negative and Y is positive. E) Both X and Y are negative.
D) X is negative and Y is positive.
n a series LRC circuit, the frequency at which the circuit is at resonance is f. If you double the resistance, the inductance, the capacitance, and the voltage amplitude of the ac source, what is the new resonance frequency? A) 4fo B) 2fo C) fo D) fo/2 E) fo/4
D) fo/2
Which one of the following lists is a correct representation of electromagnetic waves from longer wavelength to shorter wavelength? A) radio waves, infrared, microwaves, UV, visible, X‐rays, gamma rays B) radio waves, UV, X‐rays, microwaves, infrared, visible, gamma rays C) radio waves, microwaves, visible, X‐rays, infrared, UV, gamma rays D) radio waves, microwaves, infrared, visible, UV, X‐rays, gamma rays E) radio waves, infrared, X‐rays, microwaves, UV, visible, gamma rays
D) radio waves, microwaves, infrared, visible, UV, X‐rays, gamma rays
A vertical wire carries a current straight down. To the east of this wire, the magnetic field points _________. A) toward the north. B) toward the east. C) toward the west. D) toward the south. E) downward.
D) toward the south.
An electron is initially moving to the right when it enters a uniform electric field directed upwards. Which trajectory shown below will the electron follow? A) trajectory W B) trajectory X C) trajectory Y D) trajectory Z
D) trajectory Z
Two point charges of +2.0 μC and ‐6.0 μC are located on the x-axis at x = ‐1.0 cm and x = +2.0 cm respectively. Where should a third charge of +3.0-μC be placed on the +x-axis so that the potential at the origin is equal to zero? (k = 1/4πε0 = 8.99 × 10^9 N · m2/C2) A) x = 4.0 cm B) x = 1.0 cm C) x=2.0cm D) x = 3.0 cm E) x = 5.0 cm
D) x = 3.0 cm
Ions having equal charges but masses of M and 2M are accelerated through the same potential difference and then enter a uniform magnetic field perpendicular to their path. If the heavier ions follow a circular arc of radius R, what is the radius of the arc followed by the lighter? A) 4R B) 3R C) √2R D)R/√2 E) R/2
D)R/√2
When two point charges are 2.0 cm apart, each one experiences a 1.0-N electric force due to the other charge. If they are moved to a new separation of 8.0 cm, the electric force on each of them is closest to A) 1.0 N. B) 4.0 N. C) 16 N. D) 0.25 N. E) 0.063 N.
E) 0.063 N.
A rectangular loop of wire carrying a 4.0-A current is placed in a magnetic field of 0.60 T. The magnitude of the torque acting on this wire when the plane of the loop makes a 30° angle with the field is measured to be 1.1 N · m. What is the area of this loop? A) 0.20 m^2 B) 0.40 m^2 C) 0.26 m^2 D) 0.80 m^2 E) 0.53 m^2
E) 0.53 m^2
An initially-stationary electric dipole of dipole moment p = (5.00 × 10-10 C · m)î placed in an electric field E = (2.00 × 10^6 N/C) ^i + (2.00 × 10^6 N/C) j . What is the magnitude of the maximum torque that the electric field exerts on the dipole? A) 2.00 × 10^-3 N · m B) 1.40 × 10^-3 N · m C) 2.80 × 10^-3 N · m D) 0.00 N · m E) 1.00 × 10^-3 N · m
E) 1.00 × 10^-3 N · m
A parallel-plate capacitor with plate separation of 1.0 cm has square plates, each with an area of 6.0 × 10^-2 m^2. What is the capacitance of this capacitor if a dielectric material with a dielectric constant of 2.4 is placed between the plates, completely filling them? (ε0 = 8.85 × 10^-12 C^2/N · m2) A) 15 × 10^-12 F B) 15 × 10^-14 F C) 64 × 10^-14 F D) 1.3 × 10^-12 F E) 1.3 × 10^-10 F
E) 1.3 × 10^-10 F
When a potential difference of 10 V is placed across a certain solid cylindrical resistor, the current through it is 2 A. If the diameter of this resistor is now tripled, the current will be A) 2/9 A. B) 2/3 A. C) 2A. D) 3A. E) 18A.
E) 18A.
The phase angle of an LRC series circuit with a capacitive reactance of 40 Ω, a resistor of 100 Ω and a certain inductor at 1000 Hz is 40.0°. What is the value of the inductance in this circuit? A) 11.8 mH B) 124 mH C) 212 mH D) 61.9 mH E) 19.7 mH
E) 19.7 mH
A 1.0-C point charge is 15 m from a second point charge, and the electric force on one of them due to the other is 1.0 N. What is the magnitude of the second charge? (k = 1/4πε0 = 8.99 × 109 N · m2/C2) A) 25 C B) 1.0 C C) 10 nC D) 0.025 C E) 25 nC
E) 25 nC
Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions. The wires are separated by 0.20 m. What is the magnitude of the magnetic field midway between the two wires? ( μ0 = 4π × 10^-7 T · m/A) A) 1.0 × 10^-5 T B) 2.0 × 10^-5 T C) 3.0 × 10^-5 T D) 4.0 × 10^-5 T E) 5.0 × 10^-5 T
E) 5.0 × 10^-5 T
An electric field is set up between two parallel plates, each of area 2.0 m 2, by putting 1.0 μC of charge on one plate and -1.0 μC of charge on the other. The plates are separated by 4.0 mm with their centers opposite each other, and the charges are distributed uniformly over the surface of the plates. What is the magnitude of the electric field between the plates at a distance of 1.0 mm from the positive plate, but not near the edges of the plates? (ε0 = 8.85 × 10^-12 C2/N · m2) A) 4.2 × 10^4 N/C B) 1.4 × 10^4 N/C C) 3.1 × 10^4 N/C D) 0.00 N/C E) 5.6 × 10^4 N/C
E) 5.6 × 10^4 N/C
A positive point charge Q is fixed on a very large horizontal frictionless tabletop. A second positive point charge q is released from rest near the stationary charge and is free to move. Which statement best describes the motion of q after it is released? A) Its speed will be greatest just after it is released. B) Its acceleration is zero just after it is released. C) As it moves farther and farther from Q, its acceleration will keep increasing. D) As it moves farther and farther from Q, its speed will decrease. E) As it moves farther and farther from Q, its speed will keep increasing.
E) As it moves farther and farther from Q, its speed will keep increasing.
A narrow copper wire of length L and radius b is attached to a wide copper wire of length L and radius 2b, forming one long wire of length 2L. This long wire is attached to a battery, and a current is flowing through it. If the electric field in the narrow wire is E, the electric field in the wide wire is __________. A) E. B) 2E. C) 4E. D) E/2. E) E/4.
E) E/4.
When an LRC series circuit is at resonance, which one of the following statements about that circuit is accurate? (There may be more than one correct choice.) A) The impedance has its maximum value. B) The reactance of the inductor is zero. C) The reactance of the capacitor is zero. D) The reactance due to the inductor and capacitor has its maximum value. E) The current amplitude is a maximum.
E) The current amplitude is a maximum.
The figure shows a steady electric current passing through a wire with a narrow region. What happens to the drift velocity of the moving charges as they go from region A to region B and then to region C? In the figure, the wire the region go from A to C (left to right). The current flows to the right. Region B is significantly smaller/thinner than A and C. A) The drift velocity decreases from A to B and increases from B to C. B) The drift velocity increases all the time. C) Thedriftvelocityremainsconstant. D) The drift velocity decreases all the time. E) The drift velocity increases from A to B and decreases from B to C.
E) The drift velocity increases from A to B and decreases from B to C.
Two very long parallel wires are a distance d apart and carry equal currents in opposite directions. The locations where the net magnetic field due to these currents is equal to zero are __________. A) midway between the wires. B) a distance d/2 to the left of the left wire and also a distance d/2 to the right of the right wire. C) a distance d to the left of the left wire and also a distance d to the right of the right wire. D) a distance d/√2 to the left of the left wire and also a distance d/√2 to the right of the right wire. E) The net field is not zero anywhere.
E) The net field is not zero anywhere.
When electric current is flowing in a metal, the electrons are moving ________. A) at nearly the speed of light. B) at the speed of light. C) at the speed of sound in the metal. D) at the speed of sound in air. E) at none of the above speeds.
E) at none of the above speeds.
A vertical wire carries a current vertically upward in a region where the magnetic field vector points toward the north. What is the direction of the magnetic force on this current due to the field? A) downward B) toward the north C) toward the south D) toward the east E) toward the west
E) toward the west
An ideal air‐filled parallel‐plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates. All the geometric parameters of the capacitor (plate diameter and plate separation) are now DOUBLED. If the original energy density between the plates was u0, what is the new energy density? A) 16u0 B) 4u0 C) u0 D) u0/4 E) u0/16
E) u0/16
The figure shows two connected wires that are made of the same material. The current entering the wire on the left is 2.0 A and in that wire the electron drift speed is vd. What is the electron drift speed in the wire on the right side? A) 4vd B) 2vd C) vd D) vd/2 E) vd/4
E) vd/4
