Physics for IGCSE & O level - Electricity (Section 5)
1
What is the relationship between current and the number of parallel paths in a circuit?
Απάντηση
(B)
As the number of paths increases, the current increases
2
Which component is typically used to change the voltage of an AC supply?
Απάντηση
(C)
Transformer
3
What is a reed switch activated by?
Απάντηση
(C)
A magnet
4
Which of the following are correct about an appliance's power rating?
Απάντηση
A
B
C
5
What do charges do in a Van de Graaff generator?
Απάντηση
(B)
They become concentrated on the surface of a sphere
6
What are the components that constitute the basic circuit rules?
Απάντηση
A
B
C
7
What is the formula for calculating the total resistance of resistors in parallel?
Απάντηση
(B)
1/R_total = 1/R1 + 1/R2
8
Which of the following is a common example of a parallel circuit application?
Απάντηση
(C)
Household electrical wiring
9
In a series circuit, if one resistor has a voltage drop of 5V, and another has a voltage drop of 10V, what is the total voltage drop across both resistors?
Απάντηση
(C)
15V
10
Which statement best describes the role of a battery in a circuit?
Απάντηση
(C)
It provides the voltage (potential difference).
11
Which of the following describes a 'short circuit'?
Απάντηση
(B)
Low resistance and high current
12
What is the effect on the current in a circuit if the resistance is doubled while the voltage remains constant?
Απάντηση
(B)
Current halves
13
What is the frequency of the alternating current (AC) supply in most of Europe?
Απάντηση
(A)
50 Hz
14
What is the role of a live wire in a domestic electrical supply?
Απάντηση
(B)
It carries current to the appliance
15
What does the symbol 'Ω' represent in electrical circuits?
Απάντηση
(C)
Resistance
16
In a series circuit, if one component breaks, what happens to the rest of the circuit?
Απάντηση
(B)
The circuit stops working.
17
In a series circuit, if one component fails (breaks the circuit), what happens to the rest of the components?
Απάντηση
(B)
They also fail.
18
What is the unit of power?
Απάντηση
(C)
Watt
19
Which of the following are components of a simple circuit?
Απάντηση
A
B
C
D
20
If a lightbulb uses 100J of energy every second, what is its power?
Απάντηση
(A)
100 Watts
21
Which of the following is a symbol for a resistor?
Απάντηση
(D)
-///-
22
What are the parts of an atom?
Απάντηση
A
B
C
23
Which of the following is a source of AC electricity?
Απάντηση
(C)
A mains socket
24
In a circuit with a voltage source, a resistor, and a light bulb in series. If the resistance of the resistor increases, what happens to the brightness of the light bulb?
Απάντηση
(B)
The bulb will get dimmer.
25
How is resistance affected by material type?
Απάντηση
(C)
Different materials have varying resistance.
26
What is the standard voltage rating for a 3-pin plug in the UK?
Απάντηση
(C)
230V
27
Which of the following best describes the function of a variable resistor (rheostat)?
Απάντηση
(C)
To change the resistance in a circuit.
28
What happens to the overall resistance of a circuit if components are added in series?
Απάντηση
(B)
It increases
29
What is the purpose of the fuse in an electrical circuit?
Απάντηση
(C)
To break the circuit if the current exceeds a safe level.
30
What is the term for the opposition to the flow of electric current?
Απάντηση
(B)
Resistance
31
Which component opposes the flow of current in a circuit?
Απάντηση
(B)
Resistor
32
What is the unit used to measure resistance?
Απάντηση
(D)
Ohm
33
What is the effect of increasing the voltage in a circuit, assuming the resistance stays the same?
Απάντηση
(C)
The current increases
34
What component is used to block DC current and allow AC current to pass?
Απάντηση
(C)
Diode
35
In a parallel circuit, what is the same across all components?
Απάντηση
(A)
Voltage
36
Which of the following appliances is most likely to have a three-pin plug?
Απάντηση
(C)
A washing machine
37
If you plug a 1000W appliance into a 230V socket, how much current does it draw?
Απάντηση
(A)
4.35 A
38
What is a function of a fuse?
Απάντηση
(B)
To limit the current flow.
39
Which quantity is measured in Amperes (A)?
Απάντηση
(B)
Current
40
Which of the following is a unit of electrical power?
Απάντηση
(C)
Watt
41
What happens to the current in a series circuit if the voltage is increased and the resistance remains the same?
Απάντηση
(A)
The current increases
42
What are the units of voltage?
Απάντηση
(B)
Volts
43
What is the main purpose of an earth wire in an electrical appliance?
Απάντηση
(B)
To provide a path for fault current to flow to earth.
44
What is the effect of a double-insulated appliance regarding earthing?
Απάντηση
(B)
It does not require an earth wire.
45
What would be the consequence of a fuse having too high a current rating?
Απάντηση
(C)
The appliance could overheat and cause a fire.
46
Which of the following is a non-ohmic device?
Απάντηση
(C)
A diode
47
Which of the following factors does NOT affect the resistance of a wire?
Απάντηση
(D)
Weight
48
What is a key component in a simple circuit?
Απάντηση
(B)
Conductor
49
What happens to the current in a wire if the voltage is doubled and the resistance is halved?
