PHY 1402 Exam 2
A charged particle moves with a constant speed through a region where a uniform magnetic field is present. If the magnetic field points straight upward, the magnetic force acting on this particle will be strongest when the particle moves A) in a plane parallel to Earth's surface. B) upward at an angle of 45° above the horizontal. C) straight upward. D) straight downward.
A
A circular coil lies flat on a horizontal surface. A bar magnet is held above the center of the coil with its north pole pointing down. If the magnet is dropped from this position what is the direction of the induced current in the coil, as viewed from above? A) counterclockwise B) clockwise C) An emf but no current is induced in the coil. D) There is no current in the coil.
A
A closed flat loop conductor with radius 2.0m is located in a changing uniform magnetic field. If the emf induced in the loop is 2.0V what is the rate at which the magnetic field strength is changing if the magnetic field is oriented perpendicular to the plane in which the loop lies? A) 0.16 T/s B) 2.0 T/s C) 0.080 T/s D) 1.0 T/s
A
A light source radiates 60.0 W of single-wavelength sinusoidal light uniformly in all directions. What is the amplitude of the magnetic field of this light at a distance of 0.700 m from the bulb?(ε0 = 8.85 × 10^-12 C^2/N • m^2, μ0 = 4π × 10^-7 T • m/A, c = 3.0 × 10^8 m/s) A) 2.86 × 10^-7 T B) 2.02 × 10^-7 T C) 2.22 × 10^-7 T D) 1.76 × 10^-7 T
A
A radio transmitter is operating at an average power of 4.00 kW and is radiating uniformly in all directions. What is the average intensity of the signal 8.00 km from the transmitter? A) 4.97 μW/m^2 B) 0.00249 W/m^2 C) 0.00497 W/m^2 D) 2.49 μW/m^2
A
A resistor and an inductor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the inductor is A) equal to the battery's terminal voltage. B) zero. C) greater than the battery's terminal voltage. D) equal to the voltage across the resistor. E) less than the battery's terminal voltage, but not zero.
A
A sinusoidal electromagnetic wave has a peak electric field of 8.00 kV/m. What is the intensity of the wave? A) 85 kW/m^2 B) 170 kW/m^2 C) 21 kW/m^2 D) 11 kW/m^2
A
An ideal solenoid has a self-inductance L. If you now double its radius and its length, but do not change the number of coils, what will its self-inductance be? A) L/2 B) L/4 C) 4L D) 2L E) L
A
An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on a windless day. A light ray from the air above enters the oil at 45° with the normal and then goes into the water. What is the angle of refraction of this ray in the water? The index of refraction for the oil is 1.15, and for water it is 1.33. A) 32° B) 36° C) 27° D) 39°
A
As shown in the figure, one end of a metal bar is in contact with a circular rail and the other end is pivoted at P. A steady uniform, magnetic field B into the page is present. As the bar rotates about point P in a clockwise direction, the direction of the induced current through the resistor R is A) from b to a. B) from a to b. C) No current is induced.
A
As shown in the figure, two solenoids are side by side. The switch S is initially open. When S is suddenly closed, the direction of the induced current through the resistor R is A) from b to a. B) from a to b. C) No current is induced.
A
At a particular point and instant, the magnetic field component of an electromagnetic wave is 15.0 μT. What is the magnetic energy density of this wave at that point and instant? (c = 3.00 × 10^8 m/s, μ0 = 4π × 10^-7 T • m/A, ε0 = 8.85 × 10^-12 C2/N • m2) A) 8.95 × 10^-5 J/m^3 B) 2.26 × 10^-4 J/m^3 C) 4.47 × 10^-4 J/m^3 D) 9.72 × 10^-5 J/m^3 E) 1.79 × 10^-4 J/m^3
A
How far does light travel in 1.0 μs? (c = 3.0 × 10^8 m/s) A) 0.30 km B) 30 cm C) 3.0 m D) 3.0 × 10^14 m
A
If a single lens forms a virtual image of an object, then A) the lens could be either a diverging or a converging lens. B) the object must be between the lens and its focal point. C) the image must be inverted. D) the lens must be a converging lens. E) the lens must be a diverging lens.
A
If a spherical concave mirror has a radius of curvature R, its focal length is A) R/2. B) R/4. C) 2R. D) 4R. E) R.
A
If the average intensity of the sunlight in Miami, Florida, is 1060 W/m^2, what is the average magnitude of the force this light exerts on a 16-m^2 surface of black asphalt that totally absorbs the light? (c = 3.00 × 10^8 m/s) A) 5.65 × 10^-5 N B) 7.83 × 10^-5 N C) 1.63 × 10^-5 N/m^2 D) 2.61 × 10^-5 N E) 0.204 × 10^-5 N
A
If you were to cut a small permanent bar magnet in half, A) each piece would in itself be a smaller bar magnet with both north and south poles. B) one piece would be a magnetic north pole and the other piece would be a south pole. C) neither piece would be magnetic. D) None of these statements is true.
A
Sometimes when you look into a curved mirror you see a magnified image (a great big you) and sometimes you see a diminished image (a little you). If you look at the bottom (convex) side of a shiny spoon, what will you see? A)You will see a little you, right side up. B) You will either see a little you or a great big you, depending on how near you are to the spoon. C) You won't see an image of yourself because no image will be formed. D) You will see a little you, but whether you are right side up or upside down depends on how near you are to the spoon. E) You will see a little you, upside down.
A
The amplitude of the electric field for a certain type of electromagnetic wave is 570 N/C. What is the amplitude of the magnetic field for that wave? (c = 3.00 × 10^8 m/s) A) 1.90 µT B) 2.91 µT C) 2.41 µT D) 1.10 µT E) 1.41 µT
A
The index of refraction of a type of glass is 1.50, and the index of refraction of water is 1.33. If light enters water from this glass, the angle of refraction will be A) greater than the angle of incidence. B) less than the angle of incidence. C) equal to the angle of incidence.
A
Which one of the following sets of characteristics describes the image formed by a plane mirror? A) virtual and inverted B) real and inverted C) virtual and upright D) virtual and larger than the object E) real and upright
C
The wire in the figure carries a steady current I. What is true about the currents induced in each of the three loops shown? The wire and the three loops are all in the same plane. A) No current is induced in any loop. B) The currents are counterclockwise in all three loops. C) Loop A has clockwise current, loop B has no induced current, and loop C has counterclockwise current. D) Loop A has counterclockwise current, loop B has no induced current, and loop C has clockwise current. E) The currents are clockwise in all three loops.
A
Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in opposite directions, A) the wires push away from each other. B) both wires are lifted slightly. C) one wire is lifted slightly while the other wire is forced downward against the table's surface. D) the wires pull toward each other.
A
What is the wavelength used by a radio station that broadcasts at a frequency of 920 kHz? (c = 3.00 × 10^8 m/s) A) 326 m B) 226 m C) 22.6 m D) 175 m E) 276 m
A
Which one of the following is not an electromagnetic wave? A) sound waves B) infrared C) gamma rays D) ultraviolet E) radio waves
A
Which one of the following lists gives the correct order of the electromagnetic waves from longer wavelength to shorter wavelength? A) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays B) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays D) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays E) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
A
Which of the following statements is true for a series RLC ac circuit in resonance? (There could be more than one correct choice). A) The current in the circuit is a maximum. B) The inductive reactance is equal to the capacitive reactance. C) The inductive reactance and the capacitive reactance are both equal to zero. D) The current in the circuit is a minimum. E) The rms current is equal to the peak current.
A, B
A 14-mm tall postage stamp is 4.0 mm from a converging lens. If the image of the stamp is 4.0 mm tall, how far is it from the lens? A) 14 mm B) 1.1 mm C) 1.4 mm D) 8.7 mm
B
A 2.00-m long metal wire is formed into a square and placed in the horizontal xy-plane. A uniform magnetic field is oriented at 30° above the horizontal with a strength of 0.344 T. What is the magnetic flux through the square due to this field? A) 0.0745 T • m2 B) 0.0430 T • m2 C) 0.298 T • m2 D) 0.172 T • m2
B
A proton, moving in a uniform magnetic field, moves in a circle perpendicular to the field lines and takes time T for each circle. If the proton's speed tripled, what would now be its time to go around each circle? A) 3T B) T C) T/9 D) 9T E) T/3
B
A proton, moving north, enters a magnetic field. Because of this field, the proton curves downward. We may conclude that the magnetic field must have a component A) towards the north. B) towards the east. C) towards the west. D) downward. E) upward.
B
A wire lying in the plane of the page carries a current toward the bottom of the page, as shown in the figure. What is the direction of the magnetic force it produces on an electron that is moving to the left directly toward the wire, as shown? A) straight into the page B) directly toward the bottom of the page C) straight out of the page D) directly to the left away from the wire E) directly toward the top of the page
B
According to Faraday's law, a coil in a strong magnetic field must have a greater induced emf in it than a coil in a weak magnetic field. A) True B) False
B
According to Lenz's law, the induced current in a circuit always flows to oppose the external magnetic flux through the circuit. A) True B) False
B
Consider a series circuit in which the capacitive reactance equals the inductive reactance. What is the phase angle between current and voltage for this circuit? A) +90° B) 0° C) -180° D) -90° E) +180°
B
In a velocity selector consisting of perpendicular electric and magnetic fields, the speeds of the charged particles passing through the selector are increased or decreased until they are equal to the desired speed. A) True B) False
B
Light enters air from water. The angle of refraction will be A) less than the angle of incidence. B) greater than the angle of incidence. C) equal to the angle of incidence.
B
Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. What are the signs of the charges of these three particles? A) 1 is neutral, 2 is negative, and 3 is positive. B) 1 is negative, 2 is neutral, and 3 is positive. C) 1 is positive, 2 is neutral, and 3 is negative. D) 1 is positive, 2 is negative, and 3 is neutral. E) 1 is neutral, 2 is positive, and 3 is negative.
B
Two long parallel wires placed side-by-side on a horizontal table carry identical current straight toward you. From your point of view, the magnetic field at a point exactly between the two wires A) points away from you. B) is zero. C) points toward you. D) points upward. E) points downward.
B
Which one of the following lists gives the correct order of the electromagnetic spectrum from low to high frequencies? A) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays B) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays D) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
B
Which of the following are units for the magnetic moment? (There could be more than one correct choice.) A) T/(N*m) B) A • m^2 C) N • m/T D) T/m^2
B, C
Which of the following terms describe lenses that are thinner at the center than at the edges? (There could be more than one correct choice.) A) converging lenses B) diverging lenses C) convex lenses D) concave lenses
B, D
A bar magnet is oriented above a copper ring, as shown in the figure. The magnet is dropped and passes completely through the ring. As viewed from above, what is the direction of the current induced in the ring after the magnet has completely passed through the ring and is somewhat below it? A) There is no current in the ring. B) clockwise C) counterclockwise
C
A circular coil lies flat on a horizontal surface. A bar magnet is held fixed above the center of the coil with its north pole pointing downward. What is the direction of the induced current in the coil, as viewed from above? A) clockwise B) counterclockwise C) There is no current in the coil.
C
A coil lies flat on a horizontal tabletop in a region where the magnetic field points straight down. The magnetic field disappears suddenly. When viewed from above, what is the direction of the induced current in this coil as the field disappears? A) clockwise initially, then counterclockwise before stopping B) There is no induced current in this coil. C) clockwise D) counterclockwise
C
A flat coil is in a uniform magnetic field. The magnetic flux through the coil is greatest when the plane of its area is A) at 45° with the magnetic field. B) parallel to the magnetic field. C) perpendicular to the magnetic field
C
A proton has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component A) to the west. B) upward. C) to the east. D) to the north. E) downward.
C
A proton moving with a velocity of 4.0 × 10^4 m/s enters a magnetic field of 0.20 T. If the angle between the velocity of the proton and the direction of the magnetic field is 60°, what is the magnitude of the magnetic force on the proton? (e = 1.60 × 10^-19 C) A) 1.8 × 10^-15 N B) 2.2 × 10^-15 N C) 1.1 × 10^-15 N D) 0.60 × 10^-15 N E) 3.3 × 10^-15 N
C
A pure inductor is connected to an ac power supply. In this circuit, the current A) leads the voltage by 90° B) is in phase with the voltage. C) lags the voltage by 90° D) leads the voltage by 45° E) lags the voltage by 45°.
C
A transformer is a device used to A) transform an alternating current into a direct current. B) transform a direct current into an alternating current. C) increase or decrease an ac voltage. D) increase or decrease a dc voltage.
C
An 800-kHz radio signal is detected at a point 9.5 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 0.23 V/m. Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. What is the average electromagnetic energy density at that point? (c = 3.0 × 10^8 m/s, μ0 = 4π × 10^-7 T • m/A, ε0 = 8.85 × 10^-12 C2/N • m2) A) 3.3 × 10^-13 J/m^3 B) 9.4 × 10^-13 J/m^3 C) 2.3 × 10^-13 J/m^3 D) 4.7 × 10^-13 J/m^3 E) 6.6 × 10^-13 J/m^3
C
An 800-kHz sinusoidal radio signal is detected at a point 2.1 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 0.80 V/m. Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. What is the intensity of the radio signal at that point? (ε0 = 8.85 × 10^-12 C2/N • m2, μ0 = 4π × 10^-7 T • m/A, c = 3.0 × 10^8 m/s) A) 1.7 × 10-3 W/m^2 B) 6.0 × 10^-4 W/m^2 C) 8.5 × 10^-4 W/m^2 D) 1.2 × 10^-3 W/m^2 E) 4.2 × 10^-4 W/m^2
C
An ideal solenoid 20 cm long is wound with 5000 turns of very thin wire. What strength magnetic field is produced at the center of the solenoid when a current of 10 A flows through it? (μ0 = 4π × 10-7 T • m/A) A) 3.2 T B) 0.20 T C) 0.31 T D) 0.0063 T E) 4.8 T
C
An object is placed 21 cm from a concave lens having a focal length of magnitude 25 cm. What is the magnification? A) 0.22 B) -0.32 C) 0.54 D) -0.54 E) -0.22
C
An object is placed in front of a convex mirror at a distance larger than twice the magnitude of the focal length of the mirror. The image will appear A) in front of the mirror. B) upright and enlarged. C) upright and reduced. D) inverted and reduced. E) inverted and enlarged.
C
As shown in the figure, a metal bar is in contact with a pair of parallel rails. A steady, uniform, magnetic field B is present directed to the right. The bar is moving upward with velocity of magnitude ν. What is the polarity of the induced emf in terminals X and Y? A) X is positive and Y is negative. B) Y is positive and X is negative. C) X and Y are at the same potential.
C
At a certain instant, coil A is in a 10-T external magnetic field and coil B is in a 1-T external magnetic field. Both coils have the same area and are oriented at right angles to the field. Which coil will have a greater emf induced in it? A) coil A B) coil B C) It is impossible to know without more information about the fields.
C
How much current must pass through a 400-turn ideal solenoid that is 4.0 cm long to generate a 1.0-T magnetic field at the center? (μ0 = 4π × 10-7 T • m/A) A) 22 A B) 40 A C) 80 A D) 13 A E) 0.013 A
C
Light goes from material having a refractive index of n1 into a material with refractive index n2. If the refracted light is bent away from the normal, what can you conclude about the indices of refraction? A) n1 < n2 B) n1 ≥ n2 C) n1 > n2 D) n1 ≤ n2 E) n1 = n2
C
The area of a rectangular loop of wire is 3.6 × 10-3 m2. The loop is placed in a uniform magnetic field that changes steadily from 0.20 T to 1.4 T in 1.6 s. The plane of the loop is perpendicular to the direction of the magnetic field. What is the magnitude of the induced emf in that loop? A) 1.8 × 10-3 V B) 2.8 × 10-3 V C) 2.7 × 10-3 V D) 3.0 × 10-3 V E) 0 V
C
The critical angle for a beam of light passing from water into air is 48.8°. This means that all light rays with an angle of incidence in the water that is greater than 48.8° will be A) totally transmitted. B) totally absorbed by the water. C) totally reflected. D) partially reflected and partially transmitted.
C
Which one of the following expressions is the correct representation for the speed of light in vacuum? A) 1 / ε0μ0 B) sqrt(μ0/ε0) C) 1/sqrt(ε0μ0) D) sqrt(ε0μ0) E) sqrt(ε0/μ0)
C
Which one of the following statements is correct? A) When a current-carrying wire is in your right hand, with your thumb in the direction of the current, your fingers point opposite to the direction of the magnetic field lines. B) When a current-carrying wire is in your left hand, with your thumb in the direction of the current, your fingers point in the direction of the magnetic field lines. C) When a current-carrying wire is in your right hand, with your thumb in the direction of the current, your fingers point in the direction of the magnetic field lines.
C
A 7.55 × 10^14 Hz electromagnetic wave travels in carbon tetrachloride with a speed of 2.05 ×10^8 m/s. What is the wavelength of the wave in this material? A) 397 nm B) 361 nm C) 338 nm D) 272 nm E) 301 nm
D
A beam of light that is parallel to the principal axis strikes a concave mirror. What happens to the reflected beam of light? A) It is perpendicular to the principal axis. B) It also is parallel to the principal axis.It passes through the center of curvature of the mirror. C) It passes between the focal point and the center of curvature of the mirror. D) It passes through the focal point of the mirror.
D
A beam of light traveling in air strikes a slab of transparent material. The incident beam makes an angle of 40° with the normal, and the refracted beam make an angle of 26° with the normal. What is the speed of light in the transparent material? (c = 3.0 × 10^8 m/s) A) 0.50 × 10^8 m/s B) 3.0 × 10^8 m/s C) 2.3 × 10^8 m/s D) 2.0 × 10^8 m/s E) 1.0 × 10^8 m/s
D
A charged particle is observed traveling in a circular path of radius R in a uniform magnetic field. If the particle were traveling twice as fast, the radius of the circular path would be A) 4R. B) R/4. C) R/2. D) 2R. E) 8R.
D
A coin is 12 cm in front of a converging lens with focal length of magnitude 4.0 cm. Where is the image? A) 6.0 cm in front of the lens B) 4.0 cm in front of the lens C) 8.0 cm behind the lens D) 6.0 cm behind the lens
D
A convex lens has focal length f. If an object is placed at a distance between f and 2f from the lens on the principal axis, the image is located at a distance from the lens A) of 2f. B) of f. C) of infinity. D) that is greater than 2f. E) between f and 2f.
D
A flat square coil of wire with 15 turns and an area of 0.40 m2 is placed with the plane of its area parallel to a magnetic field of 0.75 T. The coil is flipped so its plane is perpendicular to the magnetic field in a time of 0.050 s. What is the magnitude of the average induced emf in the coil? A) 36 V B) 45 V C) 6.0 V D) 90 V
D
A light beam has speed c in vacuum and speed v in a certain plastic. The index of refraction n of this plastic is A) n = cv. B) n = v/c. C) n = (c/v)^2. D) n = c/v. E) n = (v/c)^2
D
A light ray in glass arrives at the glass-water interface at an angle of θ = 48° with the normal. The refracted ray in water makes an angle θ = 61° with the normal, as shown in the figure. The index of refraction of water is 1.33. The angle of incidence is now changed to θ = 25°. What is the new angle of refraction φ in the water? A) 60° B) 56° C) 62° D) 30° E) 54°
D
A radiometer has two square vanes (1.0 cm by 1.0 cm), attached to a light horizontal cross arm, and pivoted about a vertical axis through the center, as shown in the figure. The center of each vane is 6.0 cm from the axis. One vane is silvered and it reflects all radiant energy incident upon it. The other vane is blackened and it absorbs all incident radiant energy. Radiant energy, having an intensity of 300 W/m^2, is incident normally upon the front of both vanes. What is the net torque on the vane assembly, about the vertical axis? (c = 3.0 × 10^8 m/s, μ0 = 4π × 10^-7 T • m/A, ε0 = 8.85 × 10-12 C^2/N • m^2) A) 1.8 × 10^-11 N • m B) 1.2 × 10^-11 N • m C) 0.0 N • m D) 6.0 × 10^-12 N • m E) 2.4 × 10^-11 N • m
D
An ideal solenoid that is 34.0 cm long is carrying a current of 2.00 A. If the magnitude of the magnetic field generated at the center of the solenoid is 9.00 mT, how many turns of wire does this solenoid contain? (μ0 = 4π × 10-7 T • m/A) A) 860 B) 2320 C) 1590 D) 1220 E) 3180
D
Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the radius of the solenoid is doubled to 2b, but all the other quantities remain the same, the magnetic field inside the solenoid will A) become one-half as strong as initially. B) become one-fourth as strong as initially. C) become twice as strong as initially. D) remain the same. E) become four times as strong as initially.
D
For the horseshoe magnet shown in the figure, the left end is a north magnetic pole and the right end is a south magnetic pole. When the switch is closed in the circuit, which way will the wire between the poles of the horseshoe magnet initially deflect? A) to the left B) upward C) to the right D) downward
D
How far does a beam of light travel through space in one 365-day year? (c = 3.0 × 10^8 m/s) A) 80 × 10^12 m B) 30 × 10^8 m C) 36 × 10^16 m D) 95 × 10^14 m E) 20 × 10^15 m
D
If the index of refraction of a material is 2, this means that light travels A) 2 times as fast in air as it does in vacuum. B) 2 times as fast in the material than it does in vacuum. C) 2 times as fast in the material as it does in air. D) 2 times as fast in vacuum as it does in the material. E) 1/2 as fast in air as it does in the material.
D
In an electromagnetic wave in free space, the electric and magnetic fields are A) perpendicular to one another and parallel to the direction of wave propagation. B) parallel to one another and parallel to the direction of wave propagation. C) parallel to one another and perpendicular to the direction of wave propagation. D) perpendicular to one another and perpendicular to the direction of wave propagation.
D
The image formed in a plane mirror is A) at the same distance in front of the mirror as the object is in front of the mirror. B) at a shorter distance behind the mirror than the distance the object is in front of the mirror. C) at a larger distance behind the mirror than the distance the object is in front of the mirror. D) at the same distance behind the mirror as the object is in front of the mirror. E) a real image behind the mirror.
D
The rate of energy flow per unit area of an electromagnetic wave has an average value of 0.695 W/m^2. The wave is incident at right angles upon a rectangular area measuring 1.5 m by 2.0 m. How much total energy falls upon this rectangle each minute? (ε0 = 8.85 × 10^-12 C2/N • m2, μ0 = 4π × 10^-7 T • m/A, c = 3.0 × 10^8 m/s) A) 160 J B) 220 J C) 250 J D) 130 J E) 190 J
D
Which one of the following statements is correct? A) Earth's geographic south pole is the south pole of Earth's magnetic field. B) The north pole of a magnet points towards Earth's geographic south pole. C) Earth's geographic north pole is the north pole of Earth's magnetic field. D) The north pole of a magnet points towards Earth's geographic north pole. E) None of the above statements is correct.
D
Which statements about images are correct? (There could be more than one correct choice.) A) A real image must be erect. B) A virtual image cannot be photographed. C) A virtual image cannot be viewed by the unaided eye. D) A virtual image cannot be formed on a screen. E) Mirrors always produce real images because they reflect light.
D
Which of the following statements about electromagnetic waves in free space are true? (There could be more than one correct choice.) A) The wavelengths of the visible waves are some of the longest electromagnetic waves. B) The higher-frequency travel faster than the lower-frequency waves. C) The wavelengths of the visible waves are some of the shortest electromagnetic waves. D) The higher-frequency waves have shorter wavelengths than the lower-frequency waves. E) The electric field vector is always at right angles to the magnetic field vector.
D, E
A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest frequency associated with this portion of the spectrum? (c = 3.00 × 108 m/s) A) 7.50 × 10^13 Hz B) 7.50 × 10^14 Hz C) 1.50 × 10^14 Hz D) 7.50 × 10^15 Hz E) 1.50 × 10^15 Hz
E
A coil of wire containing N turns is in an external magnetic field that is perpendicular to the plane of the coil and it steadily changing. Under these circumstances, an emf ε is induced in the coil. If the rate of change of the magnetic field and the number of turns in the coil are now doubled (but nothing else changes), what will be the induced emf in the coil? A) ε/4 B) ε C) ε/2 D) 2ε E) 4ε
E
A laser beam takes 24 ms to travel from a rocket to the reflective surface of a planet and back to the rocket. How far is the rocket from this planet's surface? (c = 3.0 × 10^8 m/s) A) 2400 km B) 4800 km C) 1200 km D) 1800 km E) 3600 km
E
A light source radiates 60.0 W of single-wavelength sinusoidal light uniformly in all directions. What is the average intensity of the light from this bulb at a distance of 0.400 m from the bulb? A) 27.4 W/m^2 B) 14.9 W/m^2 C) 37.2 W/m^2 D) 11.9 W/m^2 E) 29.8 W/m^2
E
A proton is to orbit Earth at the equator using Earth's magnetic field to supply part of the necessary centripetal force. In what direction should the proton move? A) northward B) eastward C) upward D) southward E) westward
E
A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component A) downward. B) towards the east. C) towards the west. D) towards the north. E) towards the south.
E
A rectangular coil, with corners labeled ABCD, has length L and width w. It is placed between the poles of a magnet, as shown in the figure If there is a current I flowing through this coil in the direction shown, what is the direction of the force acting on section BC of this coil? A) in the opposite direction of the magnetic field B) perpendicular to and into the page C) in the direction of the magnetic field D) perpendicular to and out of the page E) The force is zero.
E
A rectangular loop of wire that can rotate about an axis through its center is placed between the poles of a magnet in a magnetic field with a strength of 0.40 T, as shown in the figure. The length of the loop L is 0.16 m and its width w is 0.040 m. What is the magnetic flux through the loop when the plane of the loop makes an angle of 60° with the magnetic field? A) 0 T • m2 B) 1.3 × 10-3 T • m2 C) 0.80 T • m2 D) 2.6 × 10-3 T • m2 E) 2.2 × 10-3 T • m2
E
A wire lying in the plane of the table carries a current directly toward the top of the table. What is the direction of the magnetic force this current produces on an electron that is moving perpendicular to the table and outward from it on the left side of the wire? A) toward the bottom of the table B) perpendicular to the table and towards you C) toward the top of the table D) perpendicular to the table and away from you E) The force is zero.
E
An 8.00-mW laser beam emits a cylindrical beam of single-wavelength sinusoidal light 0.600 mm in diameter. What is the maximum value of the magnetic field in the laser beam? (ε0 = 8.85 × 10^-12 C2/N • m^2, μ0 = 4π × 10^-7 T • m/A, c = 3.0 × 10^8 m/s) A) 9.24 µT B) 12.4 µT C) 20.5 µT D) 17.2 µT E) 15.4 µT
E
An electron moving along the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, then the magnetic field must have a component A) along the -x-axis B) along the +z-axis C) along the -y-axis D) along the +y-axis E) along the -z-axis
E
Light having a speed in vacuum of 3.0 × 10^8 m/s enters a liquid of refractive index 2.0. In this liquid, its speed will be A) 0.75 × 10^8 m/s B) 3.0 × 10^8 m/s C) 6.0 × 10^8 m/s D) 0.67 × 10^8 m/s E) 1.5 × 10^8 m/s
E
The magnetic field at point P due to a 2.0-A current flowing in a long, straight, thin wire is 8.0 μT. How far is point P from the wire? (μ0 = 4π × 10-7 T • m/A) A) 2.5 cm B) 10 cm C) 4.0 cm D) 2.0 cm E) 5.0 cm
E
Which of following statements about the image formed by a single converging lens are true? (There could be more than one correct choice.) A) The image is always upright. B) The image is always virtual. C) The image is always real. D) The image is always inverted. E) None of the above choices are correct.
E
Which one of the following numbers is the correct magnification produced by a plane mirror? A) 2 B) 1/4 C) 1/2 D) 3/2 E) 1
E
Which one of the following types of electromagnetic wave travels through space the fastest? A) ultraviolet B) microwaves C) infrared D) radio waves E) They all travel through space at the same speed.
E
