Q: Given two point charges, $$q_1 = -25$$\ \mu\mathrm{C}$$ and q_2$ = +50\ \mu\mathrm{C}$$, separated by $$d = 10.0\ \mathrm{cm}$$, what is the magnitude of the electric field at a point $$2.0\ \mathrm{cm}$$ from $$q_1 on $$the line joining the charges? Use $$k = 9.0 \times 10^9$\ \mathrm{N\cdot m^2$/C^2$$}$.

$$E = 2.7 \times 10^8$\ \mathrm{N/C}$$

Q: A point charge $$Q$$ creates an electric potential $$V = +160\ \mathrm{V} at a $$distance $$r = 25\ \mathrm{cm}. $$What is the value of $$Q$$? Use $$k = 9.0 \times 10^9$\ \mathrm{N\cdot m^2$/C^2$$}$.

$$Q = 4.4 \times 10$$^{-9}$$\ \mathrm{C}$$

Question 1

A neutral metal rod is brought into contact with a positively charged metal object, as shown in Figure 16-6. What is the resulting charge on the metal rod, and what is the process called?

Accepted Answer

The rod becomes positively charged; this is called charging by conduction.

Question 2

In Figure 16-7, a charged object is brought near a neutral metal rod, causing a separation of charge but not a net charge. If the rod is then cut in half, what happens to the charges on each part?

Accepted Answer

Each part will have a net charge, one positive and one negative.

Question 3

A charged object is brought near a nonconductor, as shown in Figure 16-9. What happens to the charges within the nonconductor?

Accepted Answer

Charge separation occurs within the molecules of the nonconductor.

Question 4

Which of the following best describes the process of charging an electroscope by induction, as shown in Figure 16-11(a)?

Accepted Answer

A charged object is brought near the electroscope, and the electroscope is grounded, allowing charge to flow.

Question 5

According to Coulomb's law, what is the direction of the force between two like charges?

Accepted Answer

The force is repulsive and directed away from each other.

Question 6

Given two point charges, $$q_1 = -25$$\ \mu\mathrm{C}$$ and q_2$ = +50\ \mu\mathrm{C}$$, separated by $$d = 10.0\ \mathrm{cm}$$, what is the magnitude of the electric field at a point $$2.0\ \mathrm{cm}$$ from $$q_1 on $$the line joining the charges? Use $$k = 9.0 	imes 10^9$\ \mathrm{N\cdot m^2$/C^2$$}$.

Accepted Answer

$$E = 2.7 	imes 10^8$\ \mathrm{N/C}$$

Question 7

Which statement about electric field lines is correct?

Accepted Answer

Electric field lines start on positive charges and end on negative charges.

Question 8

A point charge $$Q$$ creates an electric potential $$V = +160\ \mathrm{V} at a $$distance $$r = 25\ \mathrm{cm}. $$What is the value of $$Q$$? Use $$k = 9.0 	imes 10^9$\ \mathrm{N\cdot m^2$/C^2$$}$.

Accepted Answer

$$Q = 4.4 	imes 10$$^{-9}$$\ \mathrm{C}$$

Question 9

What is the equivalent capacitance of three capacitors, $$C_1 = 3.00$$\ \mu\mathrm{F}$$ and C_2$ = 4.00\ \mu\mathrm{F} in $$series, connected in parallel with $$C_3 = 2.00$$\ \mu\mathrm{F}$$?

Accepted Answer

$$C_{eq} = 3.68\ \mu\mathrm{F}$$

Question 10

A 12.0 V car battery has a terminal voltage of 8.4 V when the starter motor draws 89 A. What is the internal resistance $$r of $$the battery?

Accepted Answer

$$r = 0.040\ \Omega$$

Question 11

Which of the following best describes the electric field inside a neutral spherical metal shell with a charge at its center, as shown in Figure 16-34?

Accepted Answer

The electric field inside the conductor is zero.

Question 12

A uniform electric field $$\vec{E}$$ passes through a flat square area $$A at an $$angle $$	heta to $$the normal of the area. What is the electric flux $$\Phi_E$$ through the area?

Accepted Answer

$$\Phi_E = EA \cos 	heta$$

Question 13

Which of the following statements about equipotential lines and electric field lines for a dipole is correct?

Accepted Answer

Equipotential lines are always perpendicular to electric field lines.

Question 14

If a $$-7.6\ \mu\mathrm{C}$$ charge is moved by an electric field from ground to a point whose potential is $$+70\ \mathrm{V}$$ higher, how much work does the field do?

Accepted Answer

$$W = -5.8 	imes 10$$^{-4}$$\ \mathrm{J}$$

Question 15

A 3.5-k$$\Omega$$ and a 2.2-k$$\Omega$$ resistor are connected in parallel; this combination is connected in series with a 1.5-k$$\Omega$$ resistor. What is the total resistance of the network?

Accepted Answer

$$R_{eq} = 2.1\ \mathrm{k}\Omega$$

Question 16

A 120-V fish-tank heater is rated at 160 W. What is the current through the heater when it is operating?

Accepted Answer

$$I = 1.33\ \mathrm{A}$$

Question 17

Which of the following is true about the total current at a junction in an electric circuit?

Accepted Answer

The total current entering a junction equals the total current leaving the junction.

Electric Charge, Electric Field, and Capacitance: Study Notes

Study Guide - Practice Questions

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