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Physics for IGCSE & O level - Electricity (Section 9)

1
What happens to the total resistance in a parallel circuit as you add more resistors?
Answer
(B)
The total resistance decreases.
2
In a household electrical system, which wire is connected to the earth?
Answer
(C)
Earth wire
3
In a series circuit, what happens if one bulb is removed?
Answer
(C)
The other bulbs go out
4
When resistors are in series, how is total resistance calculated?
Answer
(A)
R1 + R2 + ...
5
If the current is constant and the voltage increases, what happens to the resistance?
Answer
(A)
Increases
6
Which safety measures regarding electrical appliances?
Answer
A
B
C
7
If the voltage across a resistor is doubled, and the resistance remains the same, what happens to the current?
Answer
(B)
It doubles.
8
In a series circuit, if one lamp breaks, what happens to the others?
Answer
(C)
They go off.
9
If a circuit has a potential difference of 12V and a resistance of 4 ohms, how much current flows?
Answer
(A)
3 amps
10
What is the relationship between current and resistance, with voltage held constant?
Answer
(B)
Inversely proportional
11
How is resistance calculated?
Answer
(B)
R = V / I
12
What type of circuit provides multiple paths for current to flow?
Answer
(B)
Parallel circuit
13
In a series circuit, if the voltage across a resistor is 6V, and the current through it is 2A, what is the resistance?
Answer
(A)
3 Ohms
14
Which way does current flow?
Answer
(B)
From positive to negative
15
What is alternating current (a.c.)?
Answer
(C)
Current that reverses direction
16
What is the definition of 'electrical current'?
Answer
(B)
The flow of electric charge.
17
What is the function of a transformer?
Answer
(B)
To change the voltage of an AC supply.
18
What does the amount of work done per unit charge represent?
Answer
(C)
Potential difference
19
What device is designed to blow if the current is too high?
Answer
(A)
A fuse
20
What type of electricity is typically used in homes and businesses?
Answer
(B)
Alternating Current (AC)
21
Which of these is NOT an application of the heating effect of an electric current?
Answer
(D)
LED light
22
What does the fuse protect?
Answer
(D)
All of the above
23
What is the SI unit for resistance?
Answer
(C)
Ohm
24
In a series of cells, how are the positive and negative terminals usually connected?
Answer
(C)
Positive to negative
25
What happens to the total current when a parallel circuit adds more branches?
Answer
(A)
Increases
26
What type of circuit has multiple paths for current to flow?
Answer
(B)
Parallel circuit
27
What is the primary function of earthing?
Answer
(B)
To provide a path for charge to flow to the ground.
28
What happens to total resistance if you add another resistor in parallel to an existing parallel circuit?
Answer
(B)
Decreases
29
What does a multimeter measure?
Answer
(A)
Voltage, current, and resistance
30
If you have two 10-ohm resistors in parallel, what is the total resistance?
Answer
(A)
5 ohms
31
What is a variable resistor often used for?
Answer
(A)
Controlling the flow of current
32
If a circuit has a voltage of 24 volts and a current of 4 amps, what is the resistance?
Answer
(A)
6 ohms
33
If two resistors of equal value are connected in parallel, the equivalent resistance will be:
Answer
(B)
Half the value of one resistor
34
What happens to the light in a series circuit if one bulb burns out?
Answer
(C)
The other bulbs go out.
35
What happens to the brightness of a bulb if the voltage is increased?
Answer
(C)
The bulb's brightness increases
36
In a parallel circuit, what is constant across all components?
Answer
(A)
Voltage
37
What happens to the total resistance if more resistors are added in parallel?
Answer
(B)
Decreases
38
What is the main function of a fuse in a circuit?
Answer
(C)
To protect the circuit from overcurrent
39
In the context of electrical circuits, what does the term 'load' refer to?
Answer
(C)
The component that consumes electrical energy
40
In a series circuit, the _______ is constant throughout the circuit.
Answer
(B)
Current
41
What happens to the brightness of a lamp if the voltage across it increases?
Answer
(C)
It becomes brighter.
42
What is the main purpose of a fuse in an electrical circuit?
Answer
(B)
To prevent excessive current flow.
43
What is the effect of increasing the length of a wire on its resistance?
Answer
(A)
Resistance increases
44
In a series circuit, if the current is 2 amps, what is the current through each component?
Answer
(B)
2 amps
45
What does 'e.m.f.' stand for?
Answer
(C)
Electromotive Force
46
If you add more resistors in parallel, how does the total resistance change?
Answer
(B)
Decreases
47
What happens to the total current in a series circuit if one component fails?
Answer
(C)
The current becomes zero
48
Which of the following statements correctly describes the purpose of a ground wire?
Answer
(C)
To provide a low-resistance path for fault current.
49
What is the total resistance of two resistors (10 ohms and 20 ohms) connected in parallel?
Answer
(C)
6.67 ohms
50
What is the function of a switch in a circuit?
Answer
(C)
To open or close the circuit