Question 1

A wire carries a current $$I$$ that is increasing with time at a constant rate. Three loops (A, B, and C) are placed in the same plane as the wire. Which statement best describes the induced currents in the loops?

Accepted Answer

Loop A has clockwise current, loop B has no induced current, and loop C has counterclockwise current.

Question 2

A battery supplies a steady current to a solenoid on the left. The two solenoids are moving toward each other with speed $$v. $$What is the direction of the induced current through the resistor $$R$$?

Accepted Answer

From b to a

Question 3

Refer to the image of four magnets falling through loops. Which magnet is least accelerated?

Accepted Answer

(d) \u003c (c) \u003c (a) = (b)

Question 4

An ideal solenoid has a self-inductance $$L. If $$you double its radius and its length, but do not change the number of coils, what will its self-inductance be?

Accepted Answer

$$4L$$

Question 5

A simple AC circuit is composed of a capacitor connected across the terminals of an AC power source. If the frequency of the source is doubled, what happens to the reactance of the capacitor?

Accepted Answer

It decreases by a factor of 2.

Question 6

Which phasor diagram represents a series RLC circuit driven at resonance?

Accepted Answer

(iii)

Question 7

An outer metal ring surrounds an inner metal ring. If the outer ring is connected to an AC power source, what is the direction of the induced current in the inner ring?

Accepted Answer

Periodic change between clockwise and counterclockwise

Question 8

Each metal bar is in contact with a pair of parallel rails and is in motion with an upward velocity $$v. $$Uniform magnetic fields are applied but their directions differ in each case. Which light-bulb(s) will glow?

Accepted Answer

(ii) and (iv)

Question 9

A resistor, a capacitor, and an inductor are connected in series to an AC source. The current in the circuit oscillates as shown. Curves (i), (ii), and (iii) show possible voltage waveforms. Which option correctly identifies the voltages across the resistor, capacitor, and inductor?

Accepted Answer

R-(i), C-(ii), L-(iii)

Question 10

Among the following hydrogen-atom transitions, which one produces the longest wavelength?

Accepted Answer

$$n = 5 \rightarrow n = 3$$

Question 11

A metal ring is placed in a magnetic field region. If the magnetic field changes with time, will an induced current always flow in the ring?

Accepted Answer

True

Question 12

If the induced voltage in the secondary coil of an ideal transformer is twice as large, then the current in the secondary coil is also twice as large. Is this statement true?

Accepted Answer

False

Question 13

If an ideal inductor is connected to an AC power source, is any power dissipation expected in the inductor?

Accepted Answer

False

Question 14

At resonance, does any current flow through the inductor in an RLC circuit connected to an AC power source?

Accepted Answer

False

Question 15

Can an isolated bound hydrogen atom produce a continuous emission spectrum?

Accepted Answer

False

Question 16

A transformer is used to step up the voltage from 120 V to 480 V. If the primary coil has 100 turns, how many turns must the secondary coil have?

Accepted Answer

400 turns

Question 17

A capacitor in an AC circuit has a reactance $$X_C = \frac{1}{\omega C}. If $$the frequency is tripled, what happens to $$X_C$$?

Accepted Answer

It decreases by a factor of 3.

Question 18

A solenoid with $$N$$ turns, length $$l$$, and radius $$r$$ has inductance $$L = \mu_0$ \frac{N^2$ A}{l}. If$$ $$N is $$doubled and $$l is $$halved, what happens to $$L$$?

Accepted Answer

It increases by a factor of 4.

Question 19

A hydrogen atom transition emits a photon with energy $$E = h 
u. If $$the transition is from $$n=4 to$$ $$n=2$$, which formula gives the energy?

Accepted Answer

$$E = 13.6 \left( \frac{1}{2^2$} - \frac{1}{4^2$} \right) eV$$

Question 20

A metal bar moves upward with velocity $$v in a $$magnetic field $$\vec{B}$$ directed into the page. What is the direction of the induced current?

Accepted Answer

From right to left

PHYS 113 - Introduction to Physics II: Review 4 – Step-by-Step Study Guidance

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