Current Electricity Practice Questions
KCSE (Kenya) · KCSE Physics · 136 free MCQs with instant results and detailed explanations.
136
Total
32
Easy
76
Medium
28
Hard
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Sample Questions from Current Electricity
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Q1
Easy
If a circuit contains a resistance of 20 ohms and a current of 2 amperes, what is the voltage across the circuit?
A.
40 volts
B.
10 volts
C.
20 volts
D.
50 volts
Show Answer & Explanation
Correct Answer: A
Using Ohm's Law (V = I Ć R), where V is voltage, I is current, and R is resistance, we calculate voltage: V = 2 A Ć 20 Ī© = 40 V.
Q2
Easy
In a series circuit with two resistors, R1 = 5 ohms and R2 = 15 ohms, what is the total resistance?
A.
20 ohms
B.
10 ohms
C.
15 ohms
D.
5 ohms
Show Answer & Explanation
Correct Answer: A
In a series circuit, total resistance is the sum of individual resistances: R_total = R1 + R2 = 5 Ī© + 15 Ī© = 20 Ī©.
Q3
Easy
If a circuit has a resistance of 5 ohms and a current of 2 amperes, what is the voltage across the circuit?
A.
7 Volts
B.
5 Volts
C.
10 Volts
D.
2 Volts
Show Answer & Explanation
Correct Answer: C
Using Ohm's Law (V = I * R), the voltage (V) can be calculated as V = 2 A * 5 Ī© = 10 Volts. Thus, the voltage across the circuit is 10 Volts.
Q4
Medium
What happens to the resistance of a conductor when its temperature increases?
A.
It increases.
B.
It decreases.
C.
It remains the same.
D.
It fluctuates.
Show Answer & Explanation
Correct Answer: A
The resistance of most conductors increases with an increase in temperature due to increased vibration of atoms, which hinders the flow of electrons.
Q5
Medium
A circuit contains a resistor of 12 ohms and a potential difference of 48 volts. What is the current flowing through the circuit?
A.
2 A
B.
4 A
C.
6 A
D.
8 A
Show Answer & Explanation
Correct Answer: B
Using Ohm's Law (V = IR), the current I can be calculated as I = V/R. Thus, I = 48V / 12Ī© = 4A.
Q6
Medium
If two resistors of 20 Ī© and 30 Ī© are connected in series, what is the total resistance?
A.
10 Ī©
B.
50 Ī©
C.
600 Ī©
D.
100 Ī©
Show Answer & Explanation
Correct Answer: B
In a series connection, the total resistance is the sum of the individual resistances. Therefore, R_total = R1 + R2 = 20Ī© + 30Ī© = 50Ī©.
Q7
Medium
In a parallel circuit with three resistors of 6 Ī©, 12 Ī©, and 18 Ī©, what is the equivalent resistance?
A.
4 Ī©
B.
6 Ī©
C.
3.6 Ī©
D.
2 Ī©
Show Answer & Explanation
Correct Answer: C
The formula for equivalent resistance in parallel is 1/R_total = 1/R1 + 1/R2 + 1/R3, which leads to R_total = 3.6Ī© after calculation.
Q8
Hard
Two resistors of 12 ohms each are connected in parallel. If a 24 V battery is connected across this combination, what is the total current supplied by the battery?
A.
2.0 A
B.
4.0 A
C.
6.0 A
D.
8.0 A
Show Answer & Explanation
Correct Answer: B
The formula for total resistance in parallel is 1/R_total = 1/R1 + 1/R2. Thus, 1/R_total = 1/12 + 1/12 = 2/12, leading to R_total = 6 ohms. Then, I = V/R_total = 24V/6Ī© = 4.0 A.
Q9
Hard
A circuit consists of a 12V battery connected in series with a resistor of 4Ī© and a 2Ī© resistor. What is the total current flowing through the circuit?
A.
3A
B.
2A
C.
1A
D.
4A
Show Answer & Explanation
Correct Answer: B
The total resistance in series is 4Ī© + 2Ī© = 6Ī©. Using Ohm's Law (V = IR), we find I = V/R = 12V/6Ī© = 2A.
Q10
Hard
In a circuit with a total resistance of 10Ī© and a current of 5A, what is the power dissipated in the circuit?
A.
50W
B.
25W
C.
100W
D.
75W
Show Answer & Explanation
Correct Answer: A
Power can be calculated using P = IĀ²R. Here, P = (5A)Ā² Ć 10Ī© = 25 Ć 10 = 250W.
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Current Electricity ā KCSE (Kenya) KCSE Physics Practice Questions Online
This page contains 136 practice MCQs for the chapter Current Electricity in KCSE (Kenya) KCSE Physics. The questions are organized by difficulty ā 32 easy, 76 medium, 28 hard ā 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.