Electricity Practice Questions
A-Levels · A-Level Physics · 136 free MCQs with instant results and detailed explanations.
136
Total
45
Easy
69
Medium
22
Hard
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Sample Questions from Electricity
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Q1
Easy
A resistor of 10 ohms is connected to a voltage of 120 volts. What is the current flowing through the resistor?
A.
12 Amperes
B.
0.83 Amperes
C.
10 Amperes
D.
120 Amperes
Show Answer & Explanation
Correct Answer: A
Using Ohm's Law (V = IR), we can calculate the current (I) by rearranging the formula to I = V/R. Therefore, I = 120V / 10ฮฉ = 12A.
Q2
Easy
Which of the following statements about series and parallel circuits is true?
A.
In series circuits, the total resistance is less than any individual resistor.
B.
In parallel circuits, the total current is the sum of the currents through each branch.
C.
In series circuits, voltage is the same across each component.
D.
In parallel circuits, resistors share the same voltage and total resistance is simply the sum of individual resistances.
Show Answer & Explanation
Correct Answer: B
In parallel circuits, the total current is indeed the sum of the currents through each branch, while the voltage across each branch remains constant.
Q3
Easy
What is the unit of electric current?
A.
Coulomb
B.
Volt
C.
Ampere
D.
Ohm
Show Answer & Explanation
Correct Answer: C
The unit of electric current is 'Ampere', defined as one coulomb per second, making option C correct.
Q4
Medium
A circuit contains a 12 V battery and a resistor of 4 ฮฉ. What is the current flowing through the circuit?
A.
3 A
B.
2 A
C.
4 A
D.
1 A
Show Answer & Explanation
Correct Answer: A
Using Ohm's Law (V = IR), we calculate the current I = V/R = 12V / 4ฮฉ = 3A.
Q5
Medium
Two resistors, R1 = 6 ฮฉ and R2 = 3 ฮฉ, are connected in parallel. What is the equivalent resistance of the combination?
A.
2 ฮฉ
B.
4 ฮฉ
C.
1.5 ฮฉ
D.
9 ฮฉ
Show Answer & Explanation
Correct Answer: A
For resistors in parallel, the formula is 1/R_eq = 1/R1 + 1/R2. Here, 1/R_eq = 1/6 + 1/3 = 1/6 + 2/6 = 3/6. Thus, R_eq = 2 ฮฉ.
Q6
Medium
A charged capacitor stores 20 ยตC of charge at a voltage of 5 V. What is the capacitance of the capacitor?
A.
4 ยตF
B.
0.5 ยตF
C.
10 ยตF
D.
1 ยตF
Show Answer & Explanation
Correct Answer: A
Capacitance C is calculated using the formula C = Q/V. Thus, C = 20 ยตC / 5 V = 4 ยตF.
Q7
Medium
A resistor of resistance 10 ohms is connected to a 12V battery. What is the current flowing through the resistor?
A.
1.2 A
B.
0.8 A
C.
2.0 A
D.
0.5 A
Show Answer & Explanation
Correct Answer: A
Using Ohm's law (V = IR), we can rearrange to find I (current). Here, V = 12V and R = 10 ohms. Thus, I = V/R = 12/10 = 1.2 A.
Q8
Hard
A circuit consists of a 12V battery connected in series with a 4ฮฉ resistor and a 6ฮฉ resistor. What is the power dissipated by the 4ฮฉ resistor?
A.
8W
B.
6W
C.
4W
D.
2W
Show Answer & Explanation
Correct Answer: B
The total resistance in the circuit is 4ฮฉ + 6ฮฉ = 10ฮฉ. The current I can be found using Ohmโs law: I = V/R = 12V/10ฮฉ = 1.2A. The power dissipated in the 4ฮฉ resistor is P = IยฒR = (1.2A)ยฒ * 4ฮฉ = 5.76W, which can round to 6W when approximated to significant figures.
Q9
Hard
A capacitor of capacitance 5 ยตF is charged to a potential difference of 400 V. Calculate the energy stored in the capacitor.
A.
1.0 J
B.
0.5 J
C.
0.8 J
D.
2.0 J
Show Answer & Explanation
Correct Answer: A
The energy (U) stored in a capacitor is given by the formula U = 1/2 * C * V^2. Substituting C = 5 x 10^-6 F and V = 400 V, we get U = 1/2 * 5 x 10^-6 * (400)^2 = 1.0 J.
Q10
Hard
In a circuit, a 12 V battery is connected in series with a 4 ฮฉ resistor and a 6 ฮฉ resistor. What is the current flowing through the circuit?
A.
1.2 A
B.
2.0 A
C.
0.8 A
D.
3.0 A
Show Answer & Explanation
Correct Answer: A
The total resistance in series is R_total = R1 + R2 = 4 ฮฉ + 6 ฮฉ = 10 ฮฉ. Using Ohm's law (V = I * R), we rearrange to I = V / R_total = 12 V / 10 ฮฉ = 1.2 A.
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Practice All 136 Questions →Electricity โ A-Levels A-Level Physics Practice Questions Online
This page contains 136 practice MCQs for the chapter Electricity in A-Levels A-Level Physics. The questions are organized by difficulty โ 45 easy, 69 medium, 22 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.