Question 1

A fluorescent light bulb emits visible light by converting ultraviolet radiation. What is the primary process that generates the ultraviolet radiation inside the bulb?

Accepted Answer

Mercury atoms emit ultraviolet radiation when excited by an electric current.

Question 2

Which analogy best describes the role of a battery in an electric circuit, based on the water flow analogy?

Accepted Answer

The battery is like the pump that drives water through the pipe.

Question 3

If 6 C of charge pass through a wire in 3 seconds, what is the electric current $$I$$?

Accepted Answer

$$I = 2\ \mathrm{A}$$

Question 4

Which statement about conventional current and electron current is correct?

Accepted Answer

Conventional current is defined as the direction positive charges would flow.

Question 5

What does a light bulb 'use up' when it is part of a closed electric circuit?

Accepted Answer

It converts the chemical energy of the battery into light and heat.

Question 6

According to Kirchhoff's Current Law (Current Node Rule), what must be true at any node in a circuit?

Accepted Answer

The sum of the currents entering the node equals the sum leaving.

Question 7

A resistor has a length $$L$$, cross-sectional area $$A$$, and is made of material with resistivity $$\rho. $$What is its resistance $$R$$?

Accepted Answer

$$R = \dfrac{\rho L}{A}$$

Question 8

In an ideal wire (with zero resistance), what is the potential difference $$\Delta V_{AB}$$ between two points $$A$$ and $$B$$?

Accepted Answer

$$\Delta V_{AB} = 0$$

Question 9

A circuit contains two resistors, $$R_1$$ and $$R_2$$, in series with a battery of voltage $$V_{battery}. $$What is the current $$I$$ through the resistors?

Accepted Answer

$$I = \dfrac{V_{battery}}{R_1$ + R_2$}$$

Question 10

Given two resistors $$R_1$$ and $$R_2 in $$parallel, what is the equivalent resistance $$R_{eq}$$?

Accepted Answer

$$\dfrac{1}{R_{eq}} = \dfrac{1}{R_1$} + \dfrac{1}{R_2$}$$

Question 11

A battery is described as having an electromotive force (EMF) $$\mathcal{E}. $$What does this EMF represent?

Accepted Answer

The potential difference the battery creates between its terminals.

Question 12

If a switch in a circuit is open, what is the current $$I$$ through the switch?

Accepted Answer

$$I = 0$$

Question 13

A circuit has a battery of voltage $$V$$ and a resistor $$R$$ connected in series. If the resistor is replaced by two resistors $$R_1$$ and $$R_2 in $$parallel, what happens to the total current drawn from the battery?

Accepted Answer

The total current increases.

Question 14

In a simple circuit with a battery, a resistor, and ideal wires, what is the direction of the electric field inside the wire?

Accepted Answer

From the positive terminal to the negative terminal.

Question 15

A student connects a light bulb to a battery using wires. After the bulb is lit, what happens to the electrons in the circuit?

Accepted Answer

They continue to flow through the circuit.

Question 16

Which of the following best describes the function of a resistor in a circuit?

Accepted Answer

It opposes the flow of electric current, converting electrical energy into heat.

Question 17

If the cross-sectional area $$A of a $$wire is doubled while keeping its length $$L$$ and resistivity $$\rho$$ constant, what happens to its resistance $$R$$?

Accepted Answer

Resistance is halved.

Question 18

In a circuit, why is it convenient to define the potential at one point as $$V = 0 ($$ground)?

Accepted Answer

It allows all voltages to be measured with respect to a common reference.

Question 19

A Van de Graaff generator is used in a demonstration. When a person touches the dome, their hair stands on end. What is the best explanation for this phenomenon?

Accepted Answer

The generator charges the person, causing each hair to acquire the same type of charge and repel each other.

Electric Current, Circuits, and Resistance: Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드