Question 1

A plastic rod is rubbed with fur and then brought near another identical plastic rod that was also rubbed with fur. What will happen between the two rods, and why?

Accepted Answer

They will repel each other because they have the same type of charge.

Question 2

Which of the following best describes the process of charging by induction?

Accepted Answer

Redistributing charges within an object due to the presence of a nearby charged object, without direct contact.

Question 3

A glass rod is rubbed with silk. What type of charge does the glass rod acquire, and why?

Accepted Answer

Positive, because it loses electrons to the silk.

Question 4

Which equation correctly expresses the quantization of electric charge?

Accepted Answer

$$Q = N e$$

Question 5

A negatively charged rod is brought near a neutral metal sphere, which is then grounded. What is the final charge on the sphere after the rod and ground are removed?

Accepted Answer

The sphere is positively charged.

Question 6

Which of the following statements about polarization is correct?

Accepted Answer

Polarization causes charges to move within an object, creating regions of positive and negative charge.

Question 7

A student rubs a balloon on her hair and then sticks it to a wall. Which concept best explains why the balloon sticks?

Accepted Answer

Polarization of charges in the wall

Question 8

Which of the following is the correct formula for the magnitude of the electric force between two point charges?

Accepted Answer

$$F = k \frac{q_1$ q_2$}{r^2$}$$

Question 9

A metal ball is suspended by an insulating thread. A negatively charged rod is brought near (but does not touch) the ball. What happens to the charges in the ball?

Accepted Answer

Electrons in the ball move away from the rod, leaving the near side positively charged.

Question 10

Which of the following best describes the difference between conductors and insulators?

Accepted Answer

Conductors allow electrons to move freely; insulators do not.

Question 11

A student observes that after touching a metal sphere with a charged rod, the sphere repels the rod. What process has occurred?

Accepted Answer

Charging by conduction

Question 12

Which of the following is the correct vector equation for the electric field created by a point charge $$q at a $$distance $$r$$?

Accepted Answer

$$\vec{E} = k \frac{q}{r^2$} \hat{r}$$

Question 13

A student wants to find the $$x$$ and $$y$$ components of a vector $$\vec{a}$$ with magnitude $$a$$ and angle $$	heta$$ from the $$x-$$axis. Which equations should they use?

Accepted Answer

$$a_x = a \cos 	heta$$, $$a_y = a \sin 	heta$$

Question 14

Which of the following best describes the result of the cross product $$\vec{A} 	imes \vec{B}$$?

Accepted Answer

A vector perpendicular to both $$\vec{A}$$ and $$\vec{B}$$ with magnitude $$AB \sin 	heta.$$

Question 15

A student observes that a charged comb can pick up small pieces of paper. Which concept best explains this phenomenon?

Accepted Answer

Polarization of the paper

Question 16

Which of the following is the correct expression for the magnitude of a vector $$\vec{a}$$ with components $$a_x$$ and $$a_y$$?

Accepted Answer

$$a = \sqrt{a_x^2$ + a_y^2$}$$

Question 17

A positively charged rod is brought near a neutral metal sphere suspended by an insulating thread. What happens to the charges in the sphere?

Accepted Answer

Electrons in the sphere move toward the rod, leaving the far side positively charged.

Question 18

Which of the following best describes the superposition principle as it applies to electric forces?

Accepted Answer

The net force on a charge is the sum of the individual forces exerted by all other charges.

Question 19

A student calculates the electric field between two parallel plates with charge density $$\sigma. $$Which equation should they use?

Accepted Answer

$$E = \frac{\sigma}{\$$varepsilon_0$$}$$

Question 20

A charged particle with charge $$q$$ and mass $$m is $$placed in a uniform electric field $$E. $$What is the acceleration of the particle?

Accepted Answer

$$a = \frac{q E}{m}$$

Week 1 Lec. 1

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드