PHY112 Final Multiple Choice

A coil lies flat on a level tabletop in a region where the magnetic field vector points straight up. The magnetic field suddenly grows stronger. When viewed from above, what is the direction of the induced current in the coil as the field increases?

Clockwise

Three capacitors are connected as shown in the figure. What is the equivalent capacitance between points A and B? A) 12 uF B) 4 uC C) 7.1 uF D) 1.7 uF7 uF E) 98.0 uF

D) 1.

If the length and diameter of a wire of circular cross section are both tripled, the resistance will be: A) unchanged. B) tripled. C) increased by a factor of 9. D) 1/3 of what it originally was. E) 1/9 of what it originally was.

D) 1/3 of what it originally was.

At a distance d from a point charge Q, the energy density in its electric field is u. If we now go to a distance d/2 from the charge, what is the energy density at the new location? A) 16u B) 8u C) 4u D) 2u E) uRAD2

D) 2u

When a dielectric material is introduced between the plates of a parallel-plate capacitor and completely fills the space, the capacitance increases by a factor of 4. What is the dielectric constant of the material that was introduced? A) 0.4 B) 1/4 C) 2 D) 4 E) None of the other choices is correct

D) 4

An ideal parallel-plate capacitor has a capacitance of C. If the area of the plates is doubled and the distance between the plates is halved, what is the new capacitance? A) C/4 B) C/2 C) 2C D) 4C

D) 4C

A concave spherical mirror has a focal length of magnitude 20 cm. An object is placed 30 cm in front of the mirror on the mirror's axis. Where is the image located? A) 12 cm behind the mirror B) 12 cm in front of the mirror C) 60 cm behind the mirror D) 60 cm in front of the mirror

D) 60 cm in front of the mirror

Which statement about a single thin lens is correct? A) A converging lens always produces a real inverted image. B) A diverging lens always produces a virtual inverted image. C) A converging lens sometimes produces a real upright image. D) A diverging lens always produces a virtual upright image. E) A diverging lens produces a virtual upright image only if the object is located between the lens and its focal point.

D) A diverging lens always produces a virtual upright image.

Monochromatic coherent light shines through a pair of slits. If the distance between these slits is decreased, which of the following statements are true of the resulting interference pattern? (There could be more than one correct choice.) A) The distance between the maxima stays the same. B) The distance between the maxima decreases. C) The distance between the minima stays the same. D) The distance between the minima increases. E) The distance between the maxima increases.

D) The distance between the minima increases. E) The distance between the maxima increases.

X and Y are two initially uncharged metal spheres on insulating stands, and they are in contact with each other. A positively charged rod R is brought close to X as shown in part (a) of the figure. Sphere Y is now moved away from X, as shown in part (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.

Two stationary point charges q1 and q2 are shown in the figure along with a sketch of some field lines representing the electric field produced by them. What can you deduce from the sketch? A) q1 is negative and q2 is positive; the magnitudes are equal. B) q1 and q2 have the same sign; the magnitudes are equal. C) q1 is positive and q2 is negative; the magnitude of q1 is greater than the magnitude of q2. D) q1 is negative and q2 is positive; the magnitude of q1 is less than the magnitude of q2. E) q1 and q2 have the same sign; the magnitude of q1 is greater than the magnitude of q2.

D) q1 is negative and q2 is positive; the magnitude of q1 is less than the magnitude of q2.

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) inverted and reduced. C) inverted and enlarged. D) upright and reduced. E) upright and enlarged.

D) upright and reduced.

An object that is 10.0 cm tall is placed 37.0 cm in front of a concave mirror of focal length 18.5 cm. How tall is the image? A) 2.5 cm B) 5.0 cm C) 7.5 cm D) 20.0 cm E) 10.0 cm

E) 10.0 cm

Four resistors having resistances of 20, 40, 60, and 80 ohms are connected in series across an ideal dc voltage source. If the current through this circuit is 0.50 A, what is the voltage of the voltage source? A) 20 B) 40 C) 60 D) 80 E) 100

E) 100 V

An object that is 4.00 cm tall is placed 18.0 cm in front of a concave mirror having a focal length of 20.0 cm. What is the location of its image in relation to the mirror and what are its characteristics? A) 180 cm on the other side of mirror, real, 6.00 times bigger B) 10 cm on the other side of mirror, virtual, 10.0 times bigger C) 18 cm on the same side of mirror, virtual, 2.25 times bigger D) 20 cm on the same side of mirror, real, 10.0 times bigger E) 180 cm on the other side of mirror, virtual, 10.0 times bigger

E) 180 cm on the other side of mirror, virtual, 10.0 times bigger

In a two-slit experiment, monochromatic coherent light of wavelength 600 nm passes through a pair of slits separated by 2.20 × 10-5 m. At what angle away from the centerline does the second dark fringe occur? A) 4.70° B) 3.51° C) 3.94° D) 1.17° E) 2.34°

E) 2.34°

A beam of light in water (of refractive index of 1.33) enters a glass slab (of refractive index 1.50) at an angle of incidence of 60.0°. What is the angle of refraction in the glass? A) 27.5° B) 39.8° C) 60.0° D) 90.0° E) 50.2°

E) 50.2°

Light travels from crown glass, with a refractive index of 1.52, into water, having a refractive index of 1.33? The critical angle for this interface is closest to which one of the following angles? A) 42° B) 48° C) 53° D) 57° E) 61°

E) 61°

Two thin slits are 6.00 μm apart. Monochromatic coherent light falls on these slits, and produces a fifth-order bright interference fringe at an angle of 32.3° away from the centerline. What is the wavelength of the light? A) 164 nm B) 416 nm C) 614 nm D) 641 nm E) 672 nm

E) 676 nm

A 4.0-cm tall object is placed 60 cm in front of a converging lens of focal length of magnitude 30 cm. What are the nature and location of the image? A) The image is real, 2.5 cm tall, 30 cm on the same side as object. B) The image is virtual, 2.5 cm tall, 30 cm on the other side of the lens. C) The image is virtual, 2.0 cm tall, 15 cm on the other side of the lens. D) The image is virtual, 4.0 cm tall, 60 cm on the same side as object. E) The image is real, 4.0 cm tall, 60 cm on the other side of the lens.

E) The image is real, 4.0 cm tall, 60 cm on the other side of the lens.

A proton having a speed of 3.0 x 10^6 m/s in a direction perpendicular to a uniform magnetic field moves in a circle of radius 0.2m within the field. What is the magnitude of the magnetic field?

.16 T

A cordless phone operates at 900 MHz. What is the wavelength of the electromagnetic wave used by this phone?

0.33 m

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?

1 is negative, 2 is neutral, 3 is positive

An ideal solenoid with 400 turns has a radius of 0.040 m and is 40 cm long. If this solenoid carries a current of 12 A, what is the magnitude of the magnetic field at the center of the solenoid?

15 mT

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 km from the transmitter?

4.97 uW/m^2

A very long straight current-carrying wire produces a magnetic field of 20mT at a distance d from the wire. To measure a field of 5mT due to this wire, you would have to go a distance from the wire of

4d

How much energy is carried by a photon of light having frequency 110 GHz?

7.3 x 10^-23

The maximum torque on a flat-current carrying loop occurs when the angle between the plane of the loop's area and the magnetic field vector is

90 degrees

Which is not an electromagnetic wave?

Sound waves

Kirchhoff's junction rule is a statement of...

The law of conservation of charge

A charge of 12 C passes through an electroplating apparatus in 2.0 min. What is the average current in the apparatus? A) 0.10 A B) 0.60 A C) 1.0 A D) 6.0 A

A) 0.10 A

An electronic component with a 17-Ω resistor is rated for use at power levels not exceeding How much current can safely flow through the component? A) 0.91 A B) 1.21 A C) 238 A D) 0.22 A

A) 0.91 A

In a two-slit experiment, monochromatic coherent light of wavelength 600 nm passes through a pair of slits separated by 2.20 x m. At what angle away from the centerline does the first bright fringe occur? A) 1.56° B) 2.22° C) 3.12° D) 4.70° E) 6.24°

A) 1.56°

A 1.4-cm tall flower is 4.0 cm from a spherical concave mirror. If the image of the flower is 4.0 cm tall, how far is the image from the mirror? A) 11 cm B) 9.4 cm C) 1.4 cm D) 0.090 cm

A) 11 cm

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) 30° B) 56° C) 54° D) 60° E) 62°

A) 30°

How far from a lens having a focal length of +50 mm must the object be placed if it is to form a virtual image that is 3.0 times the size of the object? A) 33 mm B) 42 mm C) 48 mm D) 54 mm

A) 33 mm

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation? A) 370 W B) 360 W C) 380 W D) 400 W E) 410 W

A) 370 W

Two electrons are apart at closest approach. What is the magnitude of the maximum electric force that they exert on each other A) 5.8 × 10-25 N B) 2.3 × 1010 N C) 2.3 N D) 5.8 × 10-27 N

A) 5.8 × 10-25 N

A beam of monochromatic light passes through a slit that is 11.0 μm wide. If the first order dark fringe of the resulting diffraction pattern is at an angle of 4.31° away from the centerline, what is the wavelength of light? A) 827 nm B) 301 nm C) 602 nm D) 402 nm E) 201 nm

A) 827 nm

Four point charges of equal magnitude but with varying signs are arranged on three of the corners and at the center of the square of side d as shown in the figure. Which one of the arrows shown represents the net force acting on the center charge? A) A B) B C) C D) D

A) A

Four, unequal resistors are connected in a parallel with each other. Which of the following statements is correct about this combination? A) The equivalent resistance is less than that of the smallest resistor B) The equivalent resistance is equal to the average of the four resistances C) The equivalent resistance is is midway between the largest and smallest resistance D) The equivalent resistance is is more than the largest resistance

A) The equivalent resistance is less than that of the smallest resistor

A hydrogen atom consists of a proton and an electron. If the orbital radius of the electron increases, the electric potential energy of the electron due to the proton A) increases. B) decreases. C) remains the same. D) depends on the zero point of the potential.

A) increases.

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

A) n1 > n2

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) 27° B) 32° C) 36° D) 39°

B) 32°

Light having a frequency in vacuum of 6.0 × 1014 Hz enters a liquid of refractive index 2.0. What is the frequency of the light in this liquid? (c = 3.0 × 108 m/s) A) 12 × 1014 Hz B) 6.0 × 1014 Hz C) 3.0 × 1014 Hz D) 1.5 × 1014 Hz E) 2.0 × 1014 Hz

B) 6.0 × 1014 Hz

A conductor is placed in a steady external electric field. Which of the following statements are correct for this situation? A) The electric field is zero inside the conductor. B) All the free electrons go to the surface of the conductor. C) The surface of the conductor is neutral. D) The electric field just outside the surface of the conductor is parallel to the surface. E) None of the above statements are correct.

B) All the free electrons go to the surface of the conductor.

Suppose you have two capacitors and want to use them to store the maximum amount of energy by connecting them across a voltage source. You should connect them... A) in series across the source B) in parallel across the source C) it doesn't matter because the stored energy is the same either way

B) In parallel across the source

The plates of a parallel-plate capacitor are maintained with constant voltage by a battery as they are pulled apart. What happens to the strength of the electric field between the plates during this process? A) It increases. B) It decreases. C) It remains constant. D) It cannot be determined from the information given.

B) It decreases.

Two beams of coherent light start out at the same point in phase and travel different paths to arrive at point P. If the maximum destructive interference is to occur at point P, the two beams must travel paths that differ by A) a whole number of wavelengths. B) an odd number of half-wavelengths. C) a whole number of half-wavelengths.

B) an odd number of half-wavelengths.

An upright object is 50 cm from a concave mirror of radius 60 cm. The character of the image is A) real and upright B) real and inverted C) virtual and upright D) virtual and inverted

B) real and inverted

20) The distance between two slits is 1.50 × m. A beam of coherent light of wavelength 600 nm illuminates these slits, and the distance between the slit and the screen is 2.00 m. What is the distance on the screen between the central bright fringe and the fourth-order bright fringe? A) 0.132 m B) 0.201 m C) 0.324 m D) 0.528 m E) 0.688 m

C) 0.324 m

Light of wavelength 610 nm is incident on a slit 0.20 mm wide and the diffraction pattern is viewed on a screen that is 1.5 m from the slit. What is the width on the screen of the central maximum? A) 0.34 cm B) 0.68 cm C) 0.92 cm D) 1.2 cm E) 1.5 cm

C) 0.92 cm

Light having a speed in vacuum of 3.0 × 108 m/s enters a liquid of refractive index 2.0. In this liquid, its speed will be A) 6.0 × 108 m/s B) 3.0 × 108 m/s C) 1.5 × 108 m/s D) 0.75 × 108 m/s E) 0.67 × 108 m/s

C) 1.5 × 108 m/s

In a single-slit diffraction experiment, the width of the slit through which light passes is reduced. What happens to the width of the central bright fringe in the resulting diffraction pattern? A) It stays the same. B) It becomes narrower. C) It becomes wider.

C) It becomes wider.

The figure shows electrons passing through a resistor. The arrow shows the direction in which the electrons are moving. Which of the following statements are correct? A) The electrons are moving slower at point b than at point a. B) The electric potential is higher at point b than at point a. C) The electric potential is lower at point b than at point a. D) The speed of the electrons at point b is the same as it is at point a.

C) The electric potential is lower at point b than at point a. D) The speed of the electrons at point b is the same as it is at point a.

What principle is responsible for light spreading as it passes through a narrow slit? A) refraction B) polarization C) diffraction D) dispersion

C) diffraction

When a beam of light, originally traveling in air, enters a piece of glass having an index of refraction of 3/2, its frequency A) increases by a factor of 3/2. B) is reduced to 2/3 its original value. C) is unaffected.

C) is unaffected.

If a single lens forms a virtual image of an object, then A) the lens must be a diverging lens. B) the lens must be a converging lens. C) the lens could be either a diverging or a converging lens. D) the image must be inverted. E) the object must be between the lens and its focal point.

C) the lens could be either a diverging or a converging lens.

Is it possible to see a virtual image? A) No, since the rays that seem to emanate from a virtual image do not in fact emanate from the image. B) No, since virtual images do not really exist. C) Yes because the rays that appear to come from a virtual image can be focused by the eye just like those from an object. D) Yes, but only by using an additional lens to form a real image before the light reaches the eye.

Yes because the rays that appear to come from a virtual image can be focused by the eye just like those from an object.