Question 1

Which of the following best describes the direction of conventional current and electron flow in a simple circuit containing a battery and a resistor?

Accepted Answer

Conventional current flows from the positive to the negative terminal, while electron flow is from negative to positive.

Question 2

A copper wire of length $$l$$ and cross-sectional area $$A$$ has resistance $$R. If $$the wire is stretched to twice its original length without changing its volume, what happens to its resistance?

Accepted Answer

$$R$$ increases by a factor of 4

Question 3

Which equation correctly expresses Ohm's Law for a resistor?

Accepted Answer

$$V = IR$$

Question 4

A device is connected to a 12 V battery and draws a current of 2 A. What is the power consumed by the device?

Accepted Answer

$$P = 24\ \mathrm{W}$$

Question 5

Which material would be the best choice for electrical wiring in a house, based on resistivity?

Accepted Answer

Copper

Question 6

A circuit contains three resistors in series: $$R_1 = 2$$\ \Omega$$, R_2$ = 3\ \Omega$$, and $$R_3 = 5$$\ \Omega$$. What is the equivalent resistance?

Accepted Answer

$$R_{eq} = 10\ \Omega$$

Question 7

Three resistors, $$R_1 = 6$$\ \Omega$$, R_2$ = 3\ \Omega$$, and $$R_3 = 2$$\ \Omega$$, are connected in parallel. What is the equivalent resistance?

Accepted Answer

$$R_{eq} = 1.09\ \Omega$$

Question 8

A light bulb is rated at 60 W when connected to a 120 V source. What is the resistance of the bulb?

Accepted Answer

$$R = 240\ \Omega$$

Question 9

Which of the following statements about the internal resistance of a battery is correct?

Accepted Answer

The terminal voltage is less than the emf when current is drawn from the battery.

Question 10

A fuse is used in household wiring primarily to:

Accepted Answer

Prevent excessive heating of wires by breaking the circuit if the current is too high

Question 11

The resistivity $$\rho of a $$metal increases with temperature according to $$\rho(T) = \$$rho_0$$[1 + \alpha(T - T_0$)]. $$What does $$\alpha$$ represent?

Accepted Answer

The temperature coefficient of resistivity

Question 12

A thermistor is a resistor whose resistance decreases as temperature increases. Which device would most likely use a thermistor?

Accepted Answer

A temperature sensor

Question 13

In a simple circuit with a battery and a resistor, what happens to the drift velocity of electrons if the cross-sectional area of the wire is doubled, keeping current constant?

Accepted Answer

It is halved

Question 14

Which of the following best explains why household appliances are connected in parallel rather than in series?

Accepted Answer

To ensure each appliance receives the same voltage

Question 15

A battery has an emf $$\epsilon = 9\ \mathrm{V}$$ and internal resistance $$r = 1\ \Omega. If a$$ $$8\ \Omega$$ resistor is connected across the battery, what is the terminal voltage?

Accepted Answer

$$8\ \mathrm{V}$$

Question 16

Which of the following is NOT a correct statement about Ohmic and non-Ohmic materials?

Accepted Answer

All metals are non-Ohmic materials.

Question 17

A heating element converts electrical energy into thermal energy. Which equation gives the rate of heat generation in the element?

Accepted Answer

$$P = VI$$

Question 18

A wire has resistance $$R at$$ $$20^\circC. If $$the temperature increases by $$30^\circC $$and the temperature coefficient $$\alpha = 0.004\ ^\circC$^{-1}$$, what is the new resistance?

Accepted Answer

$$R_{new} = R(1 + 0.12)$$

Question 19

Which of the following best describes the function of a circuit breaker in a household electrical system?

Accepted Answer

It automatically opens the circuit if the current exceeds a safe value.

Electric Current and Resistance: Physics with Calculus Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard