Physics for IGCSE & O level - Electricity (Section 11)
1
In a parallel circuit, if one branch has a resistance of 10 ohms, and another branch has a resistance of 20 ohms, which branch will have more current flowing through it?
Απάντηση
(A)
The 10-ohm branch
2
How does the diameter of a wire affect its resistance?
Απάντηση
(A)
Larger diameter = lower resistance
3
What is the unit of measurement for the amount of electrical charge?
Απάντηση
(C)
Coulomb
4
What is the effect on the total resistance of a circuit if a parallel branch is added with a very high resistance?
Απάντηση
(C)
The total resistance stays almost the same.
5
What is the function of an LED?
Απάντηση
(B)
To produce light when current flows through it
6
In a series circuit, where are the components connected?
Απάντηση
(B)
one after the other in a single path
7
What happens to the current if the voltage increases while the resistance stays constant?
Απάντηση
(B)
The current increases.
8
Which items are described as conductors?
Απάντηση
A
B
C
9
What is the term for the opposition to the flow of current in an electrical circuit?
Απάντηση
(C)
Resistance
10
What is the equivalent resistance of two 2-ohm resistors in series?
Απάντηση
(D)
4 ohms
11
Which of the following electrical hazards can cause serious injury or death?
Απάντηση
A
B
C
12
In a parallel circuit, if one resistor breaks, what happens to the other resistors?
Απάντηση
(C)
They continue to function.
13
What does the letter "I" represent in electrical circuits?
Απάντηση
(A)
Current
14
What type of current does a battery typically supply?
Απάντηση
(B)
Direct Current (DC)
15
What should you do if a wireless appliance electrocutes someone?
Απάντηση
(C)
Pull the plug if it is safe to do so, and call for help.
16
What happens when the filament temperature increases?
Απάντηση
(A)
Resistance increases
17
What is the unit for measuring electrical frequency?
Απάντηση
(C)
Hertz
18
What is the purpose of a step-down transformer?
Απάντηση
(B)
To decrease the voltage
19
Which type of resistor is affected by the amount of light shining on it?
Απάντηση
(C)
Light Dependent Resistor
20
Which of the following is a good conductor of electricity?
Απάντηση
(C)
Copper
21
What unit is used to measure electrical energy?
Απάντηση
(C)
Joule
22
Which materials would be considered as insulators?
Απάντηση
(C)
Rubber
23
What kind of current is used in the main electrical grid?
Απάντηση
(B)
Alternating current
24
What happens if you add more resistors in series?
Απάντηση
(C)
The overall resistance increases.
25
What flows through a wire to make an electric circuit work?
Απάντηση
(A)
Electrons
26
If two equal resistors are connected in parallel, the equivalent resistance is:
Απάντηση
(C)
Half the value of a single resistor
27
How is electrical power calculated?
Απάντηση
(A)
P = V x I
28
In a parallel circuit, how is the total current related to the current in each branch?
Απάντηση
(B)
The total current is the sum of the branch currents.
29
If a device uses 100 watts of power and is connected to a 230V supply, what is the current?
Απάντηση
(A)
0.43 A
30
Which type of energy is typically transformed by a light bulb?
Απάντηση
(B)
Electrical to light and heat
31
What is the name of the law that relates voltage, current, and resistance?
Απάντηση
(B)
Ohm's Law
32
How does the cross-sectional area of a conductor affect its resistance?
Απάντηση
(B)
Smaller area means higher resistance
33
What is the frequency of the mains electricity in most countries?
Απάντηση
(A)
50 Hz
34
What type of material has more resistance?
Απάντηση
(B)
Nichrome
35
If two resistors (R1 and R2) are in parallel, what happens to the current in each resistor?
Απάντηση
A
D
36
In a parallel circuit, how is the total current calculated?
Απάντηση
(C)
By summing the individual currents in each branch.
37
What formula is associated with Ohm's Law?
Απάντηση
(B)
V = IR
38
What is the relationship between potential difference and current in a metallic conductor at constant temperature?
Απάντηση
(A)
Directly proportional
39
If a 12V battery is connected to a 6-ohm resistor, what is the current flowing through the resistor?
Απάντηση
(B)
6 Amps
40
Which of these is NOT a common electrical hazard?
Απάντηση
(D)
Magnetic fields
41
What is the purpose of a light bulb filament?
Απάντηση
(C)
To produce light
42
What is the combined resistance of 10, 20, and 30 ohms resistors in series?
Απάντηση
(A)
60 ohms
43
What is the SI unit of electric charge?
Απάντηση
(D)
Coulomb
44
What is the formula for Ohm's Law?
Απάντηση
(C)
V = I * R
45
What is the unit of measurement for electrical power?
Απάντηση
(D)
Watt
46
What is the primary function of an ammeter in a circuit?
Απάντηση
(B)
To measure current
47
If two resistors are connected in parallel with equal resistances, the current will be:
Απάντηση
(A)
The same through both resistors
48
What happens to the current in a parallel circuit when a bulb burns out?
Απάντηση
(C)
The total current remains the same.
49
Which of the following is a unit of electrical power?
