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