Question
Which statement about a voltmeter is correct?
A voltmeter measures the current in a component and is connected in series with the component.
A voltmeter measures the current in a component and is connected in parallel with the component.
A voltmeter measures the potential difference (p.d.) across a component and is connected in series with the component.
A voltmeter measures the potential difference (p.d.) across a component and is connected in parallel with the component.
Answer/Explanation
Ans: D
Question
The diagram shows a potential divider circuit.
The resistance of the variable resistor is increased.
Which row shows what happens to the reading on voltmeter P and on voltmeter Q?
| reading on voltmeter P | reading on voltmeter Q |
A | decreases | decreases |
B | decreases | increases |
C | increases | decreases |
D | increases | increases |
Answer/Explanation
Ans: C
Question
An electric heater is plugged into the mains supply using a fused plug.
The current in the heater is 10 A.
The cable attached to the heater is rated at 15 A.
The fuses available are rated at 1 A, 3 A, 5 A and 13 A. Which fuse should be used?
A 1 A
B 3 A
C 5 A
D 13 A
Answer/Explanation
Ans: D
Question
An electric heater is plugged into the mains supply using a fused plug.
The current in the heater is 10 A.
The cable attached to the heater is rated at 15 A.
The fuses available are rated at 1 A, 3 A, 5 A and 13 A. Which fuse should be used?
A 1 A
B 3 A
C 5 A
D 13 A
Answer/Explanation
Ans: D
Question
A student connects a variable potential divider (potentiometer) circuit.
As the sliding terminal T is moved from R to S, what happens to the reading on the voltmeter?
A It decreases from 12 V to 0 V.
B It increases from 0 V to 12 V.
C It remains at 0 V.
D It remains at 12 V.
Answer/Explanation
Ans: B
Question
A light-dependent resistor (LDR) and a resistor R are connected in a series circuit. Light falls on the LDR.
The brightness of the light falling on the LDR decreases.
What happens to the resistance of the LDR and what happens to the reading on the ammeter?
| resistance of LDR | reading on ammeter |
A | decreases | decreases |
B | decreases | increases |
C | increases | decreases |
D | increases | increases |
Answer/Explanation
Ans: C