# DC Circuits Self Test 1

1. If a current of $3\; A$ is divided by the following circuit, the current flowing through the $4\; Ohm$ resistor is …

A)  $3\; A$
B)  $2\; A$
C)  $1,5 \;A$
D)  $1\; A$

2. The diagram at the right shows part of a circuit into which a current $I$ is flowing. Which ammeter shows the highest reading?

A)  $A_1$
B)  $A_2$
C)  $A_3$
D)  All three ammeters give the same reading

3. The diagram to the right represents a part of a circuit containing an ohmic resistor, a voltmeter and an ammeter. If the reading on the ammeter $A$ increases the reading on voltmeter $V…$

A)  increases in the same ratio.
B)  increases, but not in the same ratio.
C)  remains unchanged.
D)  decreases in the same ratio.

4. A battery is connected to two identical light bulbs in parallel as well as another identical bulb in series. An ammeter and a voltmeter are also connected as shown in the circuit diagram below.

One of the light bulbs connected in parallel is unscrewed. How will the ammeter and the voltmeter readings change?

A) increases increases
B) increases decreases
C) increases unchanged
D) decreases decreases

5. A student connects a circuit as shown in the diagram to the right. They use a source of electricity with an electromotive force (emf) of $12\; V.$

Which one of the following best gives the ammeter and voltmeter readings which the student is most likely to get with this circuit?

B) reads zero reads $12\; V$
D) very large reading reads $12 \;V$

6. Three identical resistors of $4 \;\Omega$ are connected to give a combined resistance of $6\; \Omega.$ Which of the following circuit diagrams illustrates how this was done?

A)  I
B)  II
C)  III
D)  IV

7. In the circuit to the right $B_1$, $B_2$ and $B_3$ are identical light bulbs. The internal resistance of the battery can be ignored.
Which statement is true regarding the relative brightness of the bulbs?

A) The three bulbs glow with the same brightness.
B) $B_2$ and $B_3$ glow with the same brightness but brighter than $B_1$
C) $B_2$ and $B_3$ glow with the same brightness but less brightly than $B_1$
D) $B_1$ glows brighter than $B_2$ while $B_2$ in turn glows brighter than $B_3$.

8. Two identical light bulbs, $X$ and $Y,$ are connected in series as shown in the sketch to the right.
How will the brightness of the bulbs change if switch $S$ is closed?

A) brighter brighter
B) dimmer dimmer
C) brighter not lit up
D) not lit up brighter

9. A student connects three identical resistors as shown in the sketch to the right.
The potential difference across the battery is $12\; \text{Volt.}$ What are the readings on $V_1$ and $V_2$ respectively?

A) 4 8
B) 6 6
C) 8 4
D) 9 3

10. A $9\; V$ battery is composed of six $1,5\; V$ cells, which are connected in series. Each cell has an internal resistance of $0,2\; W.$ What is the highest current that can be obtained from such a battery?

A)  $7,5\; A$
B)  $1,5\; A$
C)  $1,2 \;A$
D)  $0,3 \;A$