Coulomb (C); $$6.24 \times 10$$^{18}$$ electrons

$$I = \frac{P}{V} = \frac{60}{120} = 0.5\ \text{A}$$

Question 1

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

Accepted Answer

Conductors allow electrons to move freely, while insulators restrict electron motion.

Question 2

A glass rod is rubbed with silk, and the rod becomes positively charged. What has happened at the atomic level?

Accepted Answer

Electrons have been transferred from the glass rod to the silk.

Question 3

Which equation correctly relates the quantity of electric charge $$q$$, the number of electrons $$n$$, and the charge of a single electron $$e$$?

Accepted Answer

$$q = ne$$

Question 4

A neutral atom becomes a positive ion when:

Accepted Answer

It loses one or more electrons.

Question 5

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

Accepted Answer

A charged object is brought near a neutral object, causing a redistribution of charges without direct contact.

Question 6

What is the SI unit of electric charge, and how many electrons does it represent?

Accepted Answer

Coulomb (C); $$6.24 	imes 10$$^{18}$$ electrons

Question 7

Which law describes the relationship between electric force, charge, and distance?

Accepted Answer

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

Question 8

A copper wire is connected to a battery, and current flows. Which particles are primarily responsible for the current?

Accepted Answer

Free electrons in the copper wire

Question 9

Which of the following is true about series and parallel circuits?

Accepted Answer

Resistors in series add their resistances; resistors in parallel add the inverses of their resistances.

Question 10

A light bulb rated at 60 W is connected to a 120 V outlet. What is the current through the bulb?

Accepted Answer

$$I = \frac{P}{V} = \frac{60}{120} = 0.5\ 	ext{A}$$

Question 11

Which of the following best explains why metals are good electrical conductors?

Accepted Answer

They have many free electrons that can move easily through the material.

Question 12

If three resistors of 2 $$\Omega$$, 4 $$\Omega$$, and 6 $$\Omega$$ are connected in series, what is the total resistance?

Accepted Answer

$$R_{total} = 2 + 4 + 6 = 12\ \Omega$$

Question 13

A 9 V battery is connected to a resistor of 3 $$\Omega. $$What is the current through the resistor?

Accepted Answer

$$I = \frac{V}{R} = \frac{9}{3} = 3\ 	ext{A}$$

Question 14

Which of the following is a correct statement about electric power in a circuit?

Accepted Answer

Electric power is the product of voltage and current: $$P = IV$$

Question 15

Which of the following best describes the energy efficiency of an incandescent light bulb compared to an LED?

Accepted Answer

An incandescent bulb dissipates most energy as heat, while an LED converts more energy to light.

Question 16

A circuit contains a battery, a switch, and a resistor. When the switch is open, what happens?

Accepted Answer

No current flows because the circuit is incomplete.

Question 17

Which of the following is true about charging by conduction?

Accepted Answer

It involves direct contact and transfer of electrons between objects.

Question 18

If two batteries of 1.5 V each are connected in series, what is the total voltage supplied to the circuit?

Accepted Answer

$$V_{total} = 1.5 + 1.5 = 3.0\ 	ext{V}$$

Question 19

Which of the following is NOT a correct statement about static electricity?

Accepted Answer

Static electricity involves the continuous flow of electrons in a conductor.

Electricity: Concepts, Charge, and Circuits

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