Q: Which of the following is the magnitude of the charge of a single electron?

$$1.60 \times 10$$^{-19}$$\ \mathrm{C}$$

Question 1

Which of the following best describes the difference between electromotive force (emf) and potential difference in a circuit?

Accepted Answer

Emf is the energy supplied per unit charge by a source when no current flows, while potential difference is the energy used per unit charge between two points in a circuit when current flows.

Question 2

A battery with emf $$\varepsilon = 12.0\ \mathrm{V}$$ and internal resistance $$r = 1.0\ \Omega is $$connected to a $$5.0\ \Omega$$ resistor. What is the terminal voltage across the battery when the circuit is closed?

Accepted Answer

$$10.0\ \mathrm{V}$$

Question 3

Which equation correctly relates electric current $$I$$, charge $$\Delta Q$$, and time $$\Delta t$$?

Accepted Answer

$$I = \dfrac{\Delta Q}{\Delta t}$$

Question 4

A wire has a resistance $$R$$ given by $$R = \rho \dfrac{l}{A}$$, where $$\rho is $$resistivity, $$l is $$length, and $$A is $$cross-sectional area. If the length of the wire is doubled and the area is halved, how does the resistance change?

Accepted Answer

The resistance increases by a factor of 4.

Question 5

Which of the following materials is most likely to have the lowest resistivity?

Accepted Answer

Copper

Question 6

In a series circuit with three resistors $$R_1$$, $$R_2$$, and $$R_3$$, which of the following statements is true?

Accepted Answer

The current through each resistor is the same.

Question 7

A $$9.0\ \mathrm{V}$$ battery with internal resistance $$0.50\ \Omega is $$connected to a $$8.0\ \Omega$$ and $$4.0\ \Omega$$ resistor in parallel. What is the total resistance in the circuit?

Accepted Answer

$$2.67\ \Omega$$

Question 8

If a current of $$0.300\ \mathrm{mA}$$ flows through a circuit, how long does it take for $$1.00\ \mathrm{C} of $$charge to pass a point?

Accepted Answer

$$3333\ \mathrm{s}$$

Question 9

Which of the following best explains why the headlights of a car dim when the starter motor is engaged?

Accepted Answer

The starter draws a large current, causing the terminal voltage to drop due to the battery's internal resistance.

Question 10

Which statement about conventional current and electron flow is correct?

Accepted Answer

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

Question 11

A circuit contains three resistors in parallel: $$R_1 = 2$$\ \Omega$$, R_2$ = 4\ \Omega$$, and $$R_3 = 8$$\ \Omega$$. What is the equivalent resistance?

Accepted Answer

$$1.14\ \Omega$$

Question 12

Which factor does NOT affect the resistance of a wire?

Accepted Answer

The color of the wire's insulation

Question 13

A $$22.0\ \mathrm{V}$$ battery is connected to three resistors in series, each of $$125\ \Omega. $$What is the current through the circuit?

Accepted Answer

$$0.0587\ \mathrm{A}$$

Question 14

Which of the following is the correct unit for electric current?

Accepted Answer

Ampere ($$\mathrm{A})$$

Question 15

If the temperature of a metallic conductor increases, what generally happens to its resistance?

Accepted Answer

The resistance increases.

Question 16

A battery with emf $$\varepsilon$$ and internal resistance $$r is $$connected to an external resistor $$R. $$Which equation gives the current $$I in $$the circuit?

Accepted Answer

$$I = \dfrac{\varepsilon}{R + r}$$

Question 17

Which of the following best describes the microscopic origin of resistance in a conductor?

Accepted Answer

It is due to collisions between electrons and atoms in the material, which impede the flow of electrons.

Question 18

A $$6.0\ \Omega$$ and $$10.0\ \Omega$$ resistor are connected in series to a $$9.0\ \mathrm{V}$$ battery with $$0.50\ \Omega$$ internal resistance. What is the total current drawn from the battery?

Accepted Answer

$$0.53\ \mathrm{A}$$

Question 19

Which of the following is the magnitude of the charge of a single electron?

Accepted Answer

$$1.60 	imes 10$$^{-19}$$\ \mathrm{C}$$

Question 20

Which statement is true about the total resistance in a parallel circuit?

Accepted Answer

It is always less than the smallest individual resistance.

Electricity: Charge, Current, Potential Difference, Resistance, and Circuits

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