Q: What is the SI unit of electric charge, and what is the charge of a single electron?

Coulomb (C); $$-1.6 \times 10$$^{-19}$$ C

Q: If two charges, $$+e$$ and $$-e$$, are placed 5 cm apart in vacuum, what is the magnitude of the force between them? ($$e = 1.6 \times 10$$^{-19}$$ C, k_e = 9.0$$ \times $$10^9 Nm$^2/C$^2)$$

$$F = 9.2 \times 10$$^{-26}$$ N

Question 1

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

Accepted Answer

Conductors allow free movement of electrons throughout the material, while insulators restrict electron movement to specific locations.

Question 2

A student rubs a balloon on their hair, causing the balloon to stick to a wall. Which phenomenon explains this behavior?

Accepted Answer

Tribo-electric effect

Question 3

What is the SI unit of electric charge, and what is the charge of a single electron?

Accepted Answer

Coulomb (C); $$-1.6 	imes 10$$^{-19}$$ C

Question 4

According to the law of conservation of charge, what must be true in a closed system during a chemical reaction?

Accepted Answer

The total charge before and after the reaction must be equal.

Question 5

Which equation correctly represents Coulomb’s law for the force between two point charges?

Accepted Answer

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

Question 6

If two charges, $$+e$$ and $$-e$$, are placed 5 cm apart in vacuum, what is the magnitude of the force between them? ($$e = 1.6 	imes 10$$^{-19}$$ C, k_e = 9.0$$ 	imes $$10^9 Nm$^2/C$^2)$$

Accepted Answer

$$F = 9.2 	imes 10$$^{-26}$$ N

Question 7

Which of the following is the correct formula for Ohm’s Law?

Accepted Answer

$$U = iR$$

Question 8

A circuit contains a 4.5 V battery and two resistors in series: $$R_1 = 3$$ \Omega$$ and R_2$ = 1.5 \Omega. $$What is the current through the circuit?

Accepted Answer

$$i = 1.5 A$$

Question 9

Which statement about series and parallel resistors is correct?

Accepted Answer

In series, the total resistance is the sum of individual resistances; in parallel, the reciprocal of the total resistance is the sum of reciprocals of individual resistances.

Question 10

A circuit has three resistors in parallel: $$R_1 = 10$$ \Omega$$, R_2$ = 20 \Omega$$, and $$R_3 = 30$$ \Omega$$. What is the equivalent resistance?

Accepted Answer

$$R_{eq} = 5.45 \Omega$$

Question 11

Which device is used to measure current in a circuit, and how should it be connected?

Accepted Answer

An ammeter, connected in series with the circuit.

Question 12

A light bulb rated at 1.5 V and 0.3 A is connected to a battery. What is the power consumed by the bulb?

Accepted Answer

$$P = 0.45 W$$

Question 13

Which of the following best describes the direction of conventional current in a circuit?

Accepted Answer

From the positive terminal to the negative terminal of the battery.

Question 14

In a parallel circuit, what happens to the total current as more branches are added?

Accepted Answer

The total current increases.

Question 15

Which law states that the sum of the voltages around any closed loop in a circuit is zero?

Accepted Answer

Kirchhoff’s Voltage Law

Question 16

A resistor dissipates 0.3 W of power when a current of 0.1 A flows through it. What is the voltage across the resistor?

Accepted Answer

$$U = 3 V$$

Question 17

Which of the following is a correct statement about the behavior of electric field lines?

Accepted Answer

Field lines begin on positive charges and end on negative charges.

Question 18

A fuse in a circuit is used to:

Accepted Answer

Protect the circuit by breaking the connection if the current is too high.

Question 19

If a circuit is short-circuited (very low resistance), what happens to the current according to Ohm’s Law?

Accepted Answer

The current becomes very large.

Electric Circuits and Electrostatics: Fundamental Concepts for General Chemistry

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