Exam
Name___________________________________
MULTIPLE CHOICE.
1)
Choose the one alternative that best completes the statement or answers the question.
Figure 23.2a
Q
A
o
q = +530 nC
Q = -820 nC
1) _______
B
q
A charge Q = -820 nC is uniformly distributed on a ring of 2.4 m radius. A charge q = 530 nC is placed at
point o which is the center of the ring. Points A and B are located on the axis of the ring, as shown in
Figure 23.2a. oA = 1.8 m, and AB = 1.4 m., the work done by an external force that transports an electron
from B to A is closest to:
A) 45 eV
B) 540 eV
C) -45 eV
D) -540 eV
E) 630 eV
2) An electron is released from rest at a distance of 9 cm from a proton. How fast will the electron be moving
when it is 3 cm from the proton?
A) 1.06 x103 m/s
B) 75 m/s
C) 4.64 x105 m/s
D) 106 m/s
E) 130 m/s
2) _______
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
3) An oil droplet with 9 excess electrons is held stationary in a field of 4.9104 N/C. What is the
3) _____________
radius of the oil drop? (The density of the oil is 824 kg/m3, e=1.610-19 C)
Figure 24.7
4) In the circuit sketched in Figure 24.7, C1 = 4.7 10-6 F and C2 = 7.6 10-6 F. What must be the
capacitance Cx if the ratio V0/V1 is to be 7? (V1 is the voltage across capacitor C1.)
4) _____________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
5) The capacitance of a capacitor depends on
A) the energy stored in it.
B) the charge on it.
C) the potential difference across it.
D) More than one of these.
E) None of these.
6) An air capacitor is formed from two long conducting cylindrical shells which 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 The energy stored in the capacitor, in a one meter section of length is closest to:
A) 22 μJ
B) 8.0 μJ
C) 16 μJ
D) 5.7 μJ
E) 11 μJ
5) _______
6) _______
SHORT ANSWER.
Write the word or phrase that best completes each statement or answers the question.
Figure 26.13
7) In Figure 26.13, consider the circuit sketched. The battery has emf 10 V and negligible internal
resistance. The four resistors have resistances of R1 = 10 , R2 = 19 , R3 = 20 , and R4 = 10 ,
Calculate the rate at which heat is being generated in the resistor R4 = 10 .
MULTIPLE CHOICE.
7) _____________
Choose the one alternative that best completes the statement or answers the question.
Figure 26.5
8) In Figure 26.5, the circuit R is a variable resistance. As R is decreased
A) I1 increases, I2 decreases.
B) I1 decreases, I2 decreases.
C) I1 increases, I2 increases.
D) I1 remains unchanged, I2 increases.
E) I1 decreases, I2 increases.
8) _______
9) Which of the following is an accurate statement?
A) A "shunt" resistor is the name given the resistor placed in parallel with a galvanometer.
B) When one attaches a resistor to a galvanometer to construct a voltmeter, the current through the
galvanometer is typically much less than that through the resistor.
C) The resistance between the terminals of an ammeter should be as large as possible.
D) An ammeter is constructed by placing a resistor in series with a galvanometer.
E) An ammeter disturbs a circuit, whereas a voltmeter does not.
9) _______
Figure 28.5
10) In Figure 28.5, an irregular loop of wire carrying a current lies in the plane of the paper here. Suppose that
now the loop is distorted into some other shape while remaining in the same plane. Point P is still within
the loop. Which of the following is a true statement concerning this situation?
A) It is possible that the magnetic field at point P is zero.
B) The magnetic field at P will not change in direction when the loop is distorted.
C) The magnetic field at point P will always lie in the plane of the paper.
D) The magnetic field at point P will not change in magnitude when the loop is distorted.
E) None of these are true.
Figure 28.10
10) ______
11) In Figure 28.10, what is the magnetic field at the center of the two concentric arcs? The inner arc is of
radius 4 cm and the outer arc is of radius 6 cm. The loop carries a current of 4 A.
A) 2.09 x10-5 T
B) 4.45 x10-5 T
C) 7.14 x 10-4 T
D) 7.95 x 10-6 T
E) 3.49 x 10-6 T
11) ______
Figure 29.1
12) In Figure 29.1, a wire and a 10 ohm resistor are used to form a circuit in the shape of a square, 20 cm by
20 cm. A uniform but non-steady magnetic field is directed into the plane of the circuit. The magnitude of
the magnetic field is decreased from 1.50 T to 0.50 T in a time interval of 63 ms. The average induced
current and its direction through the resistor, in this time interval, are closest to:
A) 63 mA, from a to b
B) 95 mA, from a to b
C) 38 mA, from b to a
D) 38 mA, from a to b
E) 63 mA, from b to a
12) ______
13) The EMF produced by a generator is V = V0 cos ωt. If the angular velocity of the generator is doubled, and
everything else remains the same, the new EMF will be
A) V0 cos 1/2ωt
B) V0 cos 2ωt
C) 2V0 cos ωt
D) 2V0 cos 2ωt
E) V0 cos ωt
13) ______
14) A 70 mH solenoid inductor is wound on a form 0.80 m in length and 0.10 m in diameter. A coil is tightly
wound around the solenoid at its center. The coil resistance is 3.2 ohms. The mutual inductance of the coil
and solenoid is 56 H. At a given instant, the current in the solenoid is 180 mA and is decreasing at the
rate of 2.5 A/s. The number of turns in the winding of the solenoid is closest to:
A) 2300
B) 2400
C) 2700
D) 2600
E) 2500
14) ______
15)
15) ______
Figure 30.1a
s
60 V
R
L
An R-L circuit has a 60 V battery, a 42 H inductor, a 14 ohm resistor, and a switch S, in series, as shown.
Initially, the switch is open, and there is no magnetic flux in the inductor. At time t = 0 s the switch is
closed. In Figure 30.1a, when the time t = 2.10 s the current in the circuit is closest to:
A) 2.2 A
B) 1.4 A
C) 1.8 A
D) 4.3 A
E) 3.2 A
16) In a series RLC circuit, the 60 Hz ac source of a series circuit has a voltage amplitude of 120 V. The
capacitive and inductive reactances are 910 Ω and 260 Ω respectively. The resistance is 400 Ω. the
inductance, in mH, is closest to:
A) 690
B) 3300
C) 1600
D) 4300
E) 2600
16) ______
17) In a series RLC circuit suppose VC, VL, VR are the potential differences across the three elements. Then for
such a circuit
A) the current in the inductor will not necessarily be in phase with the current in the other two elements.
B) the voltage across the resistor will always be in phase with the applied EMF.
C) equal amounts of power will be dissipated in the inductor, the capacitor and the resistor.
D) equal amounts of power will be dissipated in the resistor, the inductor and the capacitor only when
the circuit is at resonance.
E) None of these is true.
17) ______
18) The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of
911mW/m2. The maximum value of the magnetic field in the wave is closest to:
A) 1.75 × 10-7 T
18) ______
B) 8.73 × 10-8 T
C) 4.37 × 10-8 T
D) 1.21 × 10-7 T
E) 6.18 × 10-8 T
19) An 800 kHz radio signal is detected at a point 3.2 km distant from a transmitter tower. The electric field
amplitude of the signal at that point is 690 mV/m. Assume that the signal power is radiated uniformly in
all directions and that radio waves incident upon the ground are completely absorbed. The average total
power radiated by the transmitter is closest to:
A) 9.8 × 104 W
19) ______
B) 8.1 × 104 W
C) 1.2 × 105 W
D) 1.4 × 105 W
E) 1.5 × 105 W
20) An object 2.0 cm in height is placed at the center of curvature C in front of a concave mirror. What is the
height of its image?
A) -6 cm
B) -1.0 cm
C) -1.5 cm
D) -2.0 cm
E) -0.50 cm
20) ______
21) A concave mirror has a focal length of 20 cm. A paraxial beam of light coming from a distant object forms
its image at the focal point. If a small plane mirror is placed at the center of curvature with its reflecting
side facing the focal point, where is the final image?
A) 70 cm in front of the mirror
B) 3 cm in front of the mirror
C) 60 cm in front of the mirror
D) 50 cm in front of the mirror
E) 40 cm in front of the mirror
21) ______
22) An object is placed 60 cm from a convex (converging) lens of focal length 10 cm. What is the
magnification?
A) 0.15
B) 0.10
C) -0.10
D) -0.20
E) 0.20
22) ______
23) In the two-slit experiment, monochromatic light of wavelength 600 nm passes through a pair of slits
separated by 2.20 x 10-5 m. What is the angle corresponding to the second dark fringe?
A) 1.17°
B) 4.70°
C) 3.51°
D) 3.94°
E) 2.35°
23) ______
24) In a single slit diffraction experiment, the width of the slit is 3.1 x 10-5 m and the distance from the slit to
the screen is 2.2 m. If the beam of light of wavelength 600 nm passes through the slit and forms a
diffraction pattern on the screen, what is the linear distance on the screen from the center of the diffraction
pattern to the first dark fringe?
A) 7.4 cm
B) 4.3 cm
C) 2.1 cm
D) 6.3 cm
E) 8.5 cm
24) ______
25) What is the slit spacing of a diffraction grating necessary for a 600 nm light to have a first order principal
maximum at 25.0°?
A) 5.44 μm
B) 1.42 μm
C) 4.12 μm
D) 2.01 μm
E) 3.12 μm
25) ______
26) An object is placed 60 cm from a concave (diverging) lens of focal length 10 cm. What is the
magnification?
26) ______
A) -0.14
B) 0.60
C) 0.14
D) 0.17
E) -0.17
1) D
2) D
3) 1.28 × 10-6 m
4) 4.1 × 10-5 F
5) E
6) B
7) 2.1 watts
8) E
9) A
10) B
11) E
12) E
13) D
14) B
15) A
16) A
17) E
18) B
19) B
20) D
21) C
22) D
23) E
24) B
25) B
26) C