Question 1

A lightning bolt, as seen in the first image, is an example of a sudden discharge of electric energy. If the electric potential difference between the cloud and the ground is $$1.0 	imes 10^8$ V and the total charge transferred is 20 C, what is the total energy released by the lightning bolt?

Accepted Answer

$$2.0 	imes 10^9$ J

Question 2

A hiker climbs to the top of a mountain, as shown in the second image. If the mountain is 1500 m high and the hiker has a mass of 70 kg, what is the change in gravitational potential energy from the base to the summit? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$1.03 	imes 10^6$ J

Question 3

Which of the following best describes the difference between electric potential and electric potential energy?

Accepted Answer

Electric potential is a property of the location in the field, while electric potential energy depends on both the charge and the location.

Question 4

A proton is released from rest in a uniform electric field of $$8 	imes 10^4$\ \mathrm{V/m}. $$After moving 0.5 m, what is the change in electric potential?

Accepted Answer

$$-4.0 	imes 10^4$ V

Question 5

If two positive point charges $$Q$$ and $$q$$ are separated by a distance $$R$$, and the distance is reduced to $$R/2$$, what happens to the total electric potential energy of the system?

Accepted Answer

It increases by a factor of 4

Question 6

A parallel plate capacitor is charged so that the potential difference between the plates is $$V. If $$the capacitor is then isolated and its plate separation is halved, what happens to the capacitance?

Accepted Answer

It is doubled

Question 7

A parallel plate capacitor with plates of area $$A$$ and separation $$d is $$charged so that the potential difference is $$V. If $$the capacitor is then isolated and its plate separation is halved, what happens to the energy stored in the capacitor?

Accepted Answer

It is doubled

Question 8

A parallel plate capacitor is connected to a battery and a dielectric with $$\kappa = 4 is $$inserted between the plates. What happens to the amount of charge stored on the plates?

Accepted Answer

It increases by a factor of 4

Question 9

The energy stored in a capacitor is given by which of the following equations?

Accepted Answer

$$U = \frac{1}{2}CV^2$

Question 10

A parallel plate capacitor has plates that are $$2.0\ \mathrm{cm} 	imes 3.0\ \mathrm{cm}$$ separated by $$1.0\ \mathrm{mm}. $$The maximum electric field in air is $$3.00 	imes 10^6$\ \mathrm{V/m}. $$What is the maximum charge that can be placed on this capacitor? ($$\$$varepsilon_0$$ = 8.85 	imes 10$$^{-12}$$\ \mathrm{F/m})$$

Accepted Answer

$$1.6 	imes 10$$^{-10}$$ C

Question 11

Which of the following statements is true regarding the effect of inserting a dielectric into an isolated, charged capacitor?

Accepted Answer

The capacitance increases by a factor of $$\kappa$$

Question 12

The electric potential at a distance $$r$$ from a point charge $$Q is $$given by:

Accepted Answer

$$V = \frac{kQ}{r}$$

Question 13

A parallel plate capacitor is charged at a potential $$V. A $$dielectric with $$\kappa = 4 is $$inserted between the plates while the potential remains constant. What happens to the energy stored in the capacitor?

Accepted Answer

It is increased by a factor of 4

Question 14

Which of the following is the correct relationship between electric field $$E$$ and electric potential $$V in a $$uniform field?

Accepted Answer

$$\Delta V = -Ed$$

Question 15

A parallel plate capacitor with plates of area $$A$$ and separation $$d is $$charged so that the potential difference is $$V. If $$the capacitor stays connected to the battery and the plate separation is doubled, what happens to the amount of charge on the plates?

Accepted Answer

It decreases by one-half

Question 16

The energy density $$u in a $$parallel plate capacitor is given by:

Accepted Answer

$$u = \frac{1}{2}\$$varepsilon_0$$ E^2$

Question 17

An electron is released from rest and allowed to accelerate across a potential difference of 1 volt. What is the kinetic energy gained by the electron?

Accepted Answer

$$1.6 	imes 10$$^{-19}$$ J

Question 18

Which of the following is NOT a scalar quantity?

Accepted Answer

Electric field $$E$$

Question 19

A parallel plate capacitor with plates of area $$A$$ and separation $$d is $$charged so that the potential difference is $$V. If $$the capacitor is then isolated and its plate separation is halved, what happens to the potential difference between the plates?

Accepted Answer

It is halved

CH 17

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