Question 1

A proton and an electron are placed 1 meter apart in vacuum. What is the magnitude of the electric force between them?

Accepted Answer

$$F = \frac{1}{4\pi\$$varepsilon_0$$} \frac{e^2$}{r^2$}$$

Question 2

Which of the following statements best describes Gauss’s Law?

Accepted Answer

The net electric flux through any closed surface is proportional to the total charge enclosed by that surface.

Question 3

A spherical conductor of radius $$R$$ carries a charge $$Q. $$What is the electric field just outside its surface?

Accepted Answer

$$E = \frac{1}{4\pi\$$varepsilon_0$$} \frac{Q}{R^2$}$$

Question 4

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

Accepted Answer

The energy increases because the capacitance decreases while the charge remains constant.

Question 5

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

Accepted Answer

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

Question 6

A wire carries a current $$I$$ and is placed in a uniform magnetic field $$B$$ perpendicular to the wire. What is the force per unit length on the wire?

Accepted Answer

$$\frac{F}{L} = IB$$

Question 7

A loop of wire is placed in a changing magnetic field. According to Faraday’s Law, what is induced in the loop?

Accepted Answer

An electromotive force (emf) proportional to the rate of change of magnetic flux.

Question 8

Which equation describes the speed of electromagnetic waves in vacuum?

Accepted Answer

$$c = \frac{1}{\sqrt{\mu_0$ \$$varepsilon_0$$}}$$

Question 9

A resistor ($$R$$), capacitor ($$C$$), and battery ($$V) $$are connected in series. What is the time constant for the circuit?

Accepted Answer

$$	au = RC$$

Question 10

A circuit contains two resistors ($$R_1$$ and $$R_2) in $$parallel. What is the equivalent resistance?

Accepted Answer

$$R_{eq} = \left( \frac{1}{R_1$} + \frac{1}{R_2$} \$$right)^{-1}$$

Question 11

A charged particle moves with velocity $$\vec{v}$$ perpendicular to a uniform magnetic field $$\vec{B}. $$What is the radius of its circular path?

Accepted Answer

$$r = \frac{mv}{qB}$$

Question 12

Which of the following best describes the concept of a photon?

Accepted Answer

A quantum of electromagnetic radiation with energy $$E = hf$$

Question 13

An electron in a hydrogen atom transitions from the $$n=3 to$$ $$n=2$$ energy level. What happens?

Accepted Answer

A photon is emitted with energy equal to the difference between the two levels.

Question 14

Which equation gives the energy of a photon?

Accepted Answer

$$E = hf$$

Question 15

A radioactive sample decays with a half-life of 10 years. What fraction of the sample remains after 30 years?

Accepted Answer

$$\frac{1}{8}$$

Question 16

Which law states that the sum of currents entering a junction equals the sum of currents leaving the junction?

Accepted Answer

Kirchhoff’s Current Law

Question 17

A solenoid of length $$L$$ and $$N$$ turns carries current $$I. $$What is the magnetic field inside the solenoid?

Accepted Answer

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

Question 18

Which equation represents the quantization of matter waves according to de Broglie?

Accepted Answer

$$\lambda = \frac{h}{p}$$

Question 19

A patient receives a dose of radioactive iodine ($$^{131}I) $$for thyroid imaging. If the half-life is 8 days, what fraction remains after 24 days?

Accepted Answer

$$\frac{1}{8}$$

Physics with Calculus: Electromagnetism and Introduction to Quantum Physics (Syllabus and Course Structure)

Guida di studio - Domande di pratica

Study guide - Flashcard