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Physics for IGCSE & O level - Electricity (Section 2)

1
What is the primary function of an RCD (Residual Current Device)?
Answer
(B)
To protect against electric shock
2
What is the unit of current?
Answer
(C)
Ampere
3
What happens to the total resistance when resistors are connected in parallel?
Answer
(B)
The total resistance decreases.
4
Which of the following devices has a high resistance?
Answer
(B)
A diode in one direction
5
What is the main function of a diode?
Answer
(A)
To allow current to flow in one direction only
6
In the context of electricity, what does 'p.d.' stand for?
Answer
(A)
Potential Difference
7
What is the main function of a capacitor in an electrical circuit?
Answer
(B)
To oppose changes in voltage
8
What is the main function of a resistor in a circuit?
Answer
(C)
To control current
9
What does an RCD (Residual Current Device) mainly protect against?
Answer
(C)
Electric shocks
10
What type of component allows current to flow easily in one direction and blocks it in the other?
Answer
(C)
Diode
11
What is the unit of resistance?
Answer
(C)
Ohm
12
What is the equivalent resistance of two 2-ohm resistors connected in series?
Answer
(C)
4 ohms
13
In a circuit, what unit is used to measure the flow of electric charge?
Answer
(B)
Ampere
14
What is the relationship between power, voltage, and resistance?
Answer
(C)
P = V^2 / R
15
If three equal resistors are connected in parallel, and the total resistance is 2 ohms, what is the value of each individual resistor?
Answer
(C)
6 ohms
16
What does 'p.d.' stand for in electrical circuits?
Answer
(A)
Potential Difference
17
Which law states that the current through a conductor between two points is directly proportional to the voltage across the two points?
Answer
(C)
Ohm's Law
18
What is the function of a fuse in an electrical circuit?
Answer
(B)
To limit the current
19
Which device is used to control the flow of current in a circuit?
Answer
(C)
A switch
20
In a series circuit, how does the current compare through each component?
Answer
(A)
It is the same for each
21
What type of material generally has a higher resistance?
Answer
(D)
Nichrome
22
Which of these is typically used to protect electrical equipment from overcurrent?
Answer
(B)
A fuse
23
In a parallel circuit, what happens if one of the parallel branches is opened?
Answer
(C)
The total current decreases.
24
What happens to the resistance of a metallic conductor as its temperature increases?
Answer
(B)
It increases
25
What happens to the total power in a parallel circuit compared to the sum of the power of each branch?
Answer
(B)
The total power is equal to the sum.
26
What does the 'AC' in 'AC mains' stand for?
Answer
(A)
Alternating Current
27
What does a positive charge create?
Answer
(A)
An electric field
28
What is the purpose of a rheostat in a circuit?
Answer
(C)
To change the resistance and control current.
29
What is the relationship between resistance and the temperature of a metal conductor?
Answer
(C)
As temperature increases, resistance increases.
30
In a parallel circuit, what is constant across each parallel branch?
Answer
(C)
Voltage
31
What is the function of a variable resistor (rheostat)?
Answer
(B)
To control the current
32
What type of charge does an object need to have a negative charge?
Answer
(A)
More electrons
33
In a series circuit, how is the current distributed?
Answer
(B)
The current is the same at all points.
34
What are the characteristics of a mains supply?
Answer
A
B
C
35
In a series circuit with two resistors, R1 and R2, what is the total resistance?
Answer
(C)
R1 + R2
36
What is the purpose of earthing (grounding) in an electrical system?
Answer
(A)
To provide an alternative path for current in case of a fault
37
What is the effect of adding a second battery in series to a circuit?
Answer
(A)
The voltage increases
38
What is the unit of electrical charge?
Answer
(C)
Coulomb
39
If the diameter of a wire is doubled, how does the resistance change?
Answer
(A)
Halved
40
What does a rectifier do in a circuit?
Answer
(A)
It converts AC to DC.
41
What is the meaning of the symbol 'Ω'?
Answer
(C)
Resistance
42
What is the electric current in a circuit?
Answer
(A)
The flow of charge
43
What describes the flow of electricity?
Answer
(B)
Current
44
Which device protects against electric shocks?
Answer
(B)
RCD
45
In a series circuit, what is the same across all components?
Answer
(B)
Current
46
In an AC circuit, what is the measure of how many times the current reverses direction per second?
Answer
(B)
Frequency
47
If you connect a voltmeter across a resistor, what does it measure?
Answer
(C)
The voltage across the resistor
48
Which of these is a characteristic of a series circuit?
Answer
(B)
The current is the same through all components.
49
Which of the following is a function of an RCD (Residual Current Device)?
Answer
(C)
To detect and quickly cut off the current if there is a leakage to earth.
50
Which statement correctly describes a short circuit?
Answer
(B)
Low resistance, high current