Physics for IGCSE & O level - Electricity (Section 1)
1
Which of the following is the most common type of fuse?
Απάντηση
(B)
Thermal Fuse
2
What happens to the current in a circuit if the voltage is held constant and the resistance is increased?
Απάντηση
(B)
The current decreases.
3
What happens if the current flowing through a resistor increases?
Απάντηση
(C)
The power dissipated by the resistor increases.
4
If the length of a wire is doubled, what happens to its resistance (assuming other factors are constant)?
Απάντηση
(A)
Doubles
5
What is the purpose of the neutral wire in a three-core cable?
Απάντηση
(A)
To provide a path for the current to return to the source.
6
What is the unit for measuring electrical power?
Απάντηση
(D)
Watt
7
What is the name of the point where two or more components connect in a circuit?
Απάντηση
(A)
Node
8
Which of the following is a unit of electrical energy?
Απάντηση
(C)
Joule
9
What is the unit for measuring electrical charge?
Απάντηση
(C)
Coulomb
10
What does the abbreviation LED stand for?
Απάντηση
(A)
Light Emitting Diode
11
What is the effect of adding more resistors in series in a circuit?
Απάντηση
(B)
The total resistance increases.
12
If two resistors are connected in parallel, and one resistor has a resistance of 10 ohms and the other has a resistance of 20 ohms, what is the total resistance?
Απάντηση
(B)
6.67 ohms
13
What best describes electric charge?
Απάντηση
(D)
Properties
14
What is measured in units of Watts?
Απάντηση
(D)
Power
15
How does the length of a wire affect its resistance?
Απάντηση
(C)
Longer wire, higher resistance
16
What is the unit for measuring electrical energy?
Απάντηση
(C)
Joule
17
Which of the following would become charged by rubbing it with a dry, wool cloth?
Απάντηση
(A)
PVC
18
In a parallel circuit, what happens to the total resistance if you add another resistor?
Απάντηση
(A)
Decreases
19
What kind of materials are electrical conductors?
Απάντηση
(A)
Metals
20
What is the role of a double insulated appliance?
Απάντηση
(A)
It does not have an earth wire
21
What happens to the total resistance in a series circuit if a resistor is replaced with one of a higher resistance value?
Απάντηση
(A)
The total resistance increases.
22
In an electric circuit, what is the function of an inductor?
Απάντηση
(B)
To oppose changes in current
23
What is the relationship between current (I), voltage (V), and resistance (R) in a circuit?
Απάντηση
(A)
V = I * R
24
In a circuit, the battery supplies energy which is transformed to the...
Απάντηση
(A)
Lamp
25
What is the term for the number of times the direction of current changes per second?
Απάντηση
(B)
Frequency
26
What are the two types of electric charge?
Απάντηση
(A)
Positive and negative
27
What will happen if one of the lamps in the series circuit breaks?
Απάντηση
(B)
All lamps will not light
28
What type of meter is used to measure current?
Απάντηση
(C)
An ammeter
29
What are the advantages of arranging some circuits in series?
Απάντηση
B
D
30
What is the relationship between the current and voltage in a resistor, according to Ohm's law?
Απάντηση
(B)
They are directly proportional.
31
What happens to the brightness of a lightbulb if the voltage across it increases?
Απάντηση
(B)
The bulb gets brighter.
32
Which circuit setup allows the full battery potential difference (p.d.) to reach each lamp?
Απάντηση
(B)
Parallel
33
Which of the following is a feature of double insulation?
Απάντηση
(C)
Provides two layers of insulation
34
How is the resistance of a conductor calculated?
Απάντηση
(B)
R = V / I
35
What is the function of a transformer?
Απάντηση
(B)
To change the voltage of an AC supply
36
What is the function of a variable resistor?
Απάντηση
(B)
To change the current in the circuit.
37
Which of the following is used to step-up (increase) or step-down (decrease) voltage?
Απάντηση
(C)
Transformer
38
Which of the following is a non-linear circuit element?
Απάντηση
(C)
Diode
39
What is the equivalent resistance of two 2-ohm resistors connected in parallel?
Απάντηση
(A)
1 ohm
40
How is the total current related in a parallel circuit?
Απάντηση
(B)
The total current is the sum of the currents in each branch.
41
What is the purpose of using multiple parallel paths in a circuit?
Απάντηση
(C)
To provide multiple current paths
42
What safety device is designed to protect appliances from overloads and short circuits?
Απάντηση
(C)
Fuse
43
What does a light emitting diode (LED) do?
Απάντηση
(A)
Emits light when a current flows through it.
44
Which component allows current to flow in only one direction?
Απάντηση
(C)
Diode
45
Which of the following is a typical household appliance that uses a high current?
Απάντηση
(B)
An electric iron
46
Which of the following is the unit for electrical charge?
Απάντηση
(C)
Coulomb
47
Which component is designed to limit the current in a circuit?
Απάντηση
(C)
A resistor
48
Which of the following components is a passive component?
Απάντηση
(D)
Resistor
49
What is the purpose of a fuse in a circuit?
Απάντηση
(B)
To protect the circuit from overcurrent
50
What is the main function of a capacitor in a circuit?
