Q: Which Maxwell equation describes how a changing electric field creates a magnetic field?

$\nabla \times \vec{B} = \mu_0 \vec{J} + \mu_0 \varepsilon_0 \frac{\partial \vec{E}}{\partial t}$

Q: A double-slit experiment is performed with light of wavelength $\lambda = 600\ \text{nm}$ and slit separation $d = 1.2 \times 10^{-4}\ \text{m}$. What is the angular position $\theta$ of the first-order maximum?

$\theta = \arcsin\left(\frac{\lambda}{d}\right) = \arcsin\left(\frac{600 \times 10^{-9}}{1.2 \times 10^{-4}}\right) \approx 0.29^\circ$

Q: A student connects three resistors ($2\ \Omega$, $4\ \Omega$, and $6\ \Omega$) in series to a $24\ \text{V}$ battery. What is the current through the circuit?

$I = \frac{24}{12} = 2\ \text{A}$

Question 1

Which of the following best describes Gauss' Law in the context of electric fields?

Accepted Answer

The net electric flux through any closed surface is equal to the total charge enclosed divided by the permittivity of free space: $\Phi_E = \frac{Q_{	ext{enc}}}{\varepsilon_0}$

Question 2

A parallel-plate capacitor is connected to a battery and then disconnected. If the plates are pulled apart to twice their original separation, what happens to the stored energy in the capacitor?

Accepted Answer

The stored energy increases by a factor of four: $U' = 4U$

Question 3

Which equation correctly expresses the relationship between current, voltage, and resistance in a DC circuit?

Accepted Answer

$I = \frac{V}{R}$

Question 4

A wire carries a current of $2\ 	ext{A}$ in a uniform magnetic field of $0.5\ 	ext{T}$. If the wire is $0.3\ 	ext{m}$ long and perpendicular to the field, what is the magnitude of the force on the wire?

Accepted Answer

$F = 0.3\ 	ext{N}$

Question 5

Which of the following is a correct statement of Faraday's Law of electromagnetic induction?

Accepted Answer

The induced emf in a closed loop equals the negative rate of change of magnetic flux through the loop: $\mathcal{E} = -\frac{d\Phi_B}{dt}$

Question 6

A resistor, inductor, and capacitor are connected in series to an AC source. Which equation gives the total impedance $Z$ of the circuit?

Accepted Answer

$Z = \sqrt{R^2 + (X_L - X_C)^2}$

Question 7

Which Maxwell equation describes how a changing electric field creates a magnetic field?

Accepted Answer

$
abla 	imes \vec{B} = \mu_0 \vec{J} + \mu_0 \varepsilon_0 \frac{\partial \vec{E}}{\partial t}$

Question 8

A light ray passes from air ($n=1.00$) into glass ($n=1.50$) at an angle of $30^\circ$ to the normal. What is the angle of refraction in the glass?

Accepted Answer

$19.5^\circ$

Question 9

Which of the following best describes the principle behind the operation of a transformer?

Accepted Answer

A transformer operates based on mutual induction, where a changing current in the primary coil induces an emf in the secondary coil.

Question 10

A double-slit experiment is performed with light of wavelength $\lambda = 600\ 	ext{nm}$ and slit separation $d = 1.2 	imes 10^{-4}\ 	ext{m}$. What is the angular position $	heta$ of the first-order maximum?

Accepted Answer

$	heta = \arcsin\left(\frac{\lambda}{d}ight) = \arcsin\left(\frac{600 	imes 10^{-9}}{1.2 	imes 10^{-4}}ight) \approx 0.29^\circ$

Question 11

Which of the following statements about the societal implications of electromagnetic wave technology is most accurate?

Accepted Answer

Electromagnetic wave technology has enabled global communication but also raises concerns about privacy and environmental impact.

Question 12

A student connects three resistors ($2\ \Omega$, $4\ \Omega$, and $6\ \Omega$) in series to a $24\ 	ext{V}$ battery. What is the current through the circuit?

Accepted Answer

$I = \frac{24}{12} = 2\ 	ext{A}$

Question 13

Which of the following best describes the function of a capacitor in an AC circuit?

Accepted Answer

A capacitor stores energy in the electric field and allows alternating current to pass while blocking direct current.

Question 14

A beam of white light passes through a prism and splits into its constituent colors. Which physical principle explains this phenomenon?

Accepted Answer

Dispersion, due to the wavelength dependence of the index of refraction.

Question 15

A solenoid with $N$ turns, length $l$, and carrying current $I$ produces a magnetic field inside given by:

Accepted Answer

$B = \mu_0 \frac{N}{l} I$

Question 16

Which of the following is a correct application of Ampère’s Law?

Accepted Answer

The line integral of the magnetic field around a closed loop equals $\mu_0$ times the current enclosed: $\oint \vec{B} \cdot d\vec{l} = \mu_0 I_{	ext{enc}}$

Question 17

A lens forms a real image of an object placed $30\ 	ext{cm}$ from the lens. If the image is formed $60\ 	ext{cm}$ on the other side, what is the focal length of the lens?

Accepted Answer

$f = \frac{1}{\frac{1}{d_o} + \frac{1}{d_i}} = \frac{1}{\frac{1}{30} + \frac{1}{60}} = 20\ 	ext{cm}$

Question 18

Which of the following best describes the societal responsibility of a physicist working with electromagnetic technologies?

Accepted Answer

A physicist must consider the ethical, environmental, and societal impacts of their work and communicate risks and benefits to the public.

University Physics II (PHY212) – Syllabus and Course Structure

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