# Electricity 3

1. Which one of the circuits shown in the diagram below can be used to determine the resistance of $R$ (A)  I
(B)  II
(C)  III
(D)  IV

D is correct

2. A car's starter motor draws a current of $100\; A$ at $12,0\; V$ when starting the engine. The mechanical power required to turn the engine is $960\; W.$ At what rate is energy from the battery converted to non-mechanical forms of energy?

(A)  $240\; W$
(B)  $960\; W$
(C)  $1200\; W$
(D)  $1440\; W$

A is correct

3. In the circuit shown below one of the bulbs blew. The result was that all bulbs stopped glowing. Which bulb blew? (A)  bulb a
(B)  bulb b
(C)  bulb c
(D)  bulb d

C is correct

4. Three resistors are connected to a battery as shown in the diagram. At which point in the circuit is the current the smallest? (A)  a
(B)  b
(C)  c
(D)  d

C is correct

5. In the circuit shown, the resistance of the ammeter, the battery and the connecting wires are negligible. The voltmeter has a very high resistance. The ammeter reads $1,5\; A.$ What is the reading on the voltmeter? (A)  $4\; V$
(B)  $6\; V$
(C)  $8\; V$
(D)  $12\; V$

B is correct

6. Two resistors are connected in parallel as shown in the diagram. The current flowing through the ammeter is: (A)  $0,6\; A$
(B)  $1,5\; A$
(C)  $2,5\; A$
(D)  $14,4\; A$

C is correct

7. Consider the circuit shown to the right. If switch $S$ is closed, the readings on the voltmeter and ammeter will change as follows: (A) becomes zero remains the same
(B) becomes zero increases
(C) remains the same decreases
(D) decreases increases

B is correct

8. The circuit below shows two identical bulbs, $L$ and $M,$ which are connected to a battery and a variable resistor $R.$ How will the brightness of the bulbs be affected if the resistance of $R$ is increased? (A) dimmer brighter
(B) dimmer dimmer
(C) dimmer the same
(D) brighter the same

A is correct The information given refers to questions 9 and 10:  The battery in the circuit has an internal resistance $r$ and an emf $E.$ The resistance of the ammeter and the conductors is negligible and the voltmeter has a high resistance

9. When the switch $S$ is closed, the …

(A) decreases decreases
(B) decreases increases
(C) increases decreases
(D) increases increases

B is correct

10. When the switch $S$ is closed the power in the resistors $R_1$ and R2 …

Answer Power in $R_1$ Power in $R_2$
(A) decreases decreases
(B) decreases increases
(C) increases decreases
(D) increases increases