# DC Circuits Self Test 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

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)  $1440\; W$

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

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

5. In the circuit shown below, 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)  $12 \;V$

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)  $14,4 \;A$

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

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 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. The information given above refers to questions 9 and 10

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

A decreases decreases
B decreases increases
C increases decreases
D increases increases

10. When the switch $S$ is closed the power in the resistors $R_1$ and $R_2$ …

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