Deck 6: Geometrical Optics, Electromagnetic Induction and Alternating Current

Question 1

At 3.68100017 kHz the reactance in a circuit of a 9.0 µF capacitor and an inductor are equal in magnitude. What is the value of the inductor?

A) 0.00021 ?H
B) 0.000020 mH
C) 0.00021 mH
D) 0.000020 H

Answer 1

0.00021 ?H

Question 2

What is the resonance frequency of an LC circuit consisting of a 26.0 µF capacitor and a 0.010 H inductor?

A) 0.31 kHz
B) 2.0 kHz
C) 3.2 kHz
D) 12 kHz

Answer 2

0.31 kHz

Question 3

The reactance of a capacitor is 7.0 k? at a frequency of 0.30 kHz. What is the capacitance?

A) 0.076 ?F
B) 0.48 ?F
C) 3.0 ?F
D) 0.107 ?F

Answer 3

0.076 ?F

Question 4

A conducting bar is free to slide horizontally on the rails of a conducting frame, as shown in the figure. A lightbulb is attached to the right end of the rails. A spatially uniform magnetic field is oriented vertically (perpendicular to the horizontal plane of the rails and bar). Initially the bar is stationary. The strength of the magnetic field begins increasing in time at a constant rate, which induces a current through the bar, frame, and lightbulb. The bar begins to move due to the magnetic force exerted on it. Once the bar begins to move, the brightness of the lightbulb

A) stays the same.
B) increases.
C) decreases.
D) suddenly drops to zero.

Question 5

A capacitor, initially having a charge Q on the left plate and a charge -Q on the right plate, is connected to a switch and an inductor, as shown in the figure.
Assuming the resistance of the circuit is zero, when the switch is closed,

A) charge will flow out of the capacitor until the left plate is no longer charged, and then all current ceases.
B) current will flow until the left plate of the capacitor has a charge -Q, and then current will flow in the opposite direction, reversing again when the left plate has a charge of +Q. The cycle will then repeat over and over.
C) current will flow through the inductor back and forth, with the magnitude of the current decreasing and eventually going to zero.
D) None of the above

Question 6

Calculate the speed at which a 0.272 kg object has the same momentum as a 1.30 kg object moving 0.515 c.

A) 0.944 c
B) 0.922 c
C) 0.981 c
D) 0.592 c

Question 7

Situation
A proton (rest energy = 938 MeV) has a speed of 0.80 c.

-In Situation above, the ratio of the kinetic energy of the proton to its rest energy is closest to:

A) 0.60
B) 0.67
C) 0.80
D) 1.2
E) 1.7

Question 8

Situation
A proton (rest energy = 938 MeV) has a speed of 0.80 c.

-In Situation above, the momentum of the proton in kg ? m/s is closest to:

A) 4.0 × 10^-19
B) 4.4 × 10^-19
C) 5.0 × 10^-19
D) 5.8 × 10^-19
E) 6.7 × 10^-19

Question 9

Calculate the amount of energy needed to accelerate an electron from 0.888 c to 0.991 c. Express your answer in MeV.

A) 2.71 MeV
B) 1.89 MeV
C) 4.60 MeV
D) 5.68 MeV

Question 10

A particle has speed 0.95 c and total energy 4.8 × 10^-10 J. What is its momentum?

A) 1.5 × 10^-18 kg ? m/s
B) 2.5 × 10^-15 kg ? m/s
C) 5.6 × 10^-13 kg ? m/s
D) 1.0 × 10^-9 kg ? m/s

Question 11

Free neutrons (unlike those in the nucleus of an atom) decay spontaneously into a proton, an electron, and an antineutrino. The masses of these particles are (approx.):
M_n = 1.67492 × 10^-27 kg
M_p = 1.67262 × 10^-27 kg
M_e = 9.10939 × 10^-31 kg
The mass of the neutrino is zero (or nearly so). How much energy is released in this decay?

A) 1.01 × 10^-14 J
B) 1.25 × 10^-13 J
C) 4.66 × 10^-12 J
D) 7.08 × 10^-13 J
E) 5.61 × 10^-12 J

Question 12

A gamma ray (a pulse of electromagnetic energy) has a frequency of 2.42 × 10²⁰ Hz.
What is the ratio of its wavelength to the radius of the nucleus which produced it
(radius = 5.0 × 10^-13 cm)?

A) 248
B) 39.4
C) 1.21 × 10⁸
D) 0.015

Question 13

A person buys a SUV and discovers that it is too long to fit in the garage (the length of the SUV is 1.3 times the length of the garage). He decides to drive the SUV into the garage at a speed of 0.99 c. Which statement is true?

A) A person standing near the garage sees the SUV fit inside the garage prior to it colliding into the back wall of the garage, but the driver will claim that it never was entirely inside.
B) The driver of the SUV sees that the entire SUV is inside the garage prior to it colliding into the back wall, but the person standing near the garage will claim it never was entirely inside.
C) Both the driver and the person standing near the garage will claim that the SUV was entirely inside the garage prior to the front smashing into the back wall of the garage.
D) Neither the driver nor the person standing near the garage will claim that the SUV was entirely inside the garage.

Question 14

Situation
The objective and the eyepiece of a microscope have focal lengths of 4.0 mm and 25 mm, respectively. The objective produces a real image 30 times the size of the object. The final image is viewed at infinity. The near point of the microscope user is at 25 cm.

-In Situation above, the distance between the object and the focal point of the objective, in mm, is closest to:

A) 0.13
B) 0.18
C) 0.23
D) 0.28
E) 0.33

Question 15

A mirror reverses an image from left to right but not top to bottom. Why?