Module 7: DC Circuits

Question 1

1. The brightness will decrease momentarily then return to its previous level.
2. The brightness increases permanently.
3. The brightness will increase momentarily then return to its previous level.
4. The brightness remains the same as before the switch is closed.
5. The brightness decreases permanently.

Answer 1

2. The brightness increases permanently.

Question 2

1. none of the above
2. +4 V - (8Ω) i2 - (12Ω) i1 = 0 V
3. -(8Ω) i2 + 4 V + 6 V + (12Ω) i1 = 0 V
4. +6 V - (12Ω) i1 - (8Ω) i2 + 4 V = 0 V
5. -6 V + 2 V - (6Ω) i3 = 0 V

Answer 2

4. +6 V - (12Ω) i1 - (8Ω) i2 + 4 V = 0 V

Question 3

Answer 3

A

Question 4

Answer 4

y, x, z

Question 5

Answer 5

X

Question 6

T or F: If a 75 W bulb and a 100 W bulb are connected in series across a 120 V outlet, the 75 W bulb will dissipate 75 W of power and the 100 W bulb will dissipate 100 W of power.

Answer 6

F

Question 7

1. B and C have equal brightness, and A is the dimmest.
2. A and B have equal brightness, and C is the dimmest.
3. A is brightest, C is dimmest, and B is in between.
4. A is the brightest, and B and C have equal brightness but less than A.
5. All three bulbs have the same brightness.

Answer 7

4. A is the brightest, and B and C have equal brightness but less than A

Question 8

1. closing both switches
2. closing S1 only
3. closing S2 only
4. leaving both switches open as shown

Answer 8

1. closing both switches

Question 9

A light bulb is connected in the circuit shown in the figure with the switch S open and the capacitor uncharged. The battery has no appreciable internal resistance. Which one of the following graphs best describes the brightness B of the bulb as a function of time t after closing the switch?

Answer 9

2

Question 10

1. I1 + I3 = I6 + I4
2. I4 + I3 = I6
3. I1 + I2 = I6 + I4
4. I2 = I6 + I4
5. I6 + I5 = I1

Answer 10

3. I1 + I2 = I6 + I4

Question 11

1. E2 + R3I3 + E3 - R2I2 = 0
2. E2 + R3I3 - E3 + R2I2 = 0
3. E2 - R3I3 - E3 - R2I2 = 0
4. E2 + R3I3 + E3 + R2I2 = 0
5. -E2 + R3I3 - E3 + R2I2 = 0

Answer 11

2. E2 + R3I3 - E3 + R2I2 = 0