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