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