Electricity and Magnetism Practice Questions
NECO (Nigeria) · NECO Physics · 129 free MCQs with instant results and detailed explanations.
129
Total
28
Easy
79
Medium
22
Hard
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Sample Questions from Electricity and Magnetism
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Q1
Easy
Which of the following materials is a good insulator?
A.
Copper
B.
Plastic
C.
Aluminum
D.
Gold
Show Answer & Explanation
Correct Answer: B
Plastic is a good insulator because it does not conduct electricity, unlike metals such as copper and gold.
Q2
Easy
If a circuit has a voltage of 10V and a resistance of 5ฮฉ, what is the current flowing through the circuit?
A.
2A
B.
5A
C.
10A
D.
15A
Show Answer & Explanation
Correct Answer: A
Using Ohm's Law (V = IR), current (I) can be calculated as I = V/R = 10V / 5ฮฉ = 2A.
Q3
Easy
If a resistor of 10 ohms is connected to a voltage of 20 volts, what is the current flowing through the resistor?
A.
2 Amperes
B.
20 Amperes
C.
0.5 Amperes
D.
10 Amperes
Show Answer & Explanation
Correct Answer: A
Using Ohm's Law (V = IR), we can rearrange it to find the current: I = V/R. Thus, I = 20V / 10ฮฉ = 2A.
Q4
Medium
A circuit consists of a 12V battery and a resistor of 4 ohms. What is the current flowing through the circuit?
A.
3 A
B.
4 A
C.
12 A
D.
48 A
Show Answer & Explanation
Correct Answer: A
Using Ohm's law (I = V/R), the current is 12V / 4ฮฉ = 3A.
Q5
Medium
When a magnet is moved towards a coil of wire, what type of current is induced in the coil?
A.
Direct current
B.
Alternating current
C.
No current
D.
Induced current
Show Answer & Explanation
Correct Answer: D
An induced current is generated in the coil due to electromagnetic induction when the magnet is moved towards it.
Q6
Medium
What is the total resistance in a circuit containing three resistors of 4ฮฉ, 6ฮฉ, and 12ฮฉ connected in series?
A.
22ฮฉ
B.
10ฮฉ
C.
12ฮฉ
D.
16ฮฉ
Show Answer & Explanation
Correct Answer: A
In a series circuit, the total resistance is the sum of individual resistances. Total resistance = 4ฮฉ + 6ฮฉ + 12ฮฉ = 22ฮฉ.
Q7
Medium
A wire carries a current of 10A and has a resistance of 5ฮฉ. What is the power dissipated in the wire?
A.
50W
B.
100W
C.
25W
D.
75W
Show Answer & Explanation
Correct Answer: A
Power (P) is calculated using the formula P = IยฒR. Substituting the values: P = (10A)ยฒ * 5ฮฉ = 100Aยฒ * 5ฮฉ = 500W.
Q8
Hard
A 10-ohm resistor and a 20-ohm resistor are connected in series across a 60V power supply. What is the current flowing through the circuit?
A.
2A
B.
4A
C.
6A
D.
3A
Show Answer & Explanation
Correct Answer: D
In a series circuit, the total resistance is the sum of the individual resistances. Here, R_total = 10ฮฉ + 20ฮฉ = 30ฮฉ. Using Ohm's Law (V = IR), the current I can be calculated as I = V/R_total = 60V/30ฮฉ = 2A. Therefore, the correct answer is 2A.
Q9
Hard
An electromagnet is made by winding 100 turns of wire around a core. If the current flowing through the wire is 3A, calculate the magnetic field strength (B) inside the solenoid if the core has a permeability of 1.26 x 10^-6 Tยทm/A.
A.
0.378 T
B.
0.126 T
C.
0.756 T
D.
0.252 T
Show Answer & Explanation
Correct Answer: A
The magnetic field strength inside a solenoid can be calculated using the formula B = ฮผnI, where n is the number of turns per unit length. Here, if we assume the solenoid's length is 1 m, n = 100 turns/m. So, B = (1.26 x 10^-6 Tยทm/A)(100 turns/m)(3A) = 0.378 T.
Q10
Hard
A circuit consists of a 12V battery connected to two resistors in series: R1 = 4ฮฉ and R2 = 6ฮฉ. What is the total current flowing through the circuit?
A.
0.8 A
B.
1.2 A
C.
2.0 A
D.
1.0 A
Show Answer & Explanation
Correct Answer: B
To find the total current, first calculate the total resistance (R_total) of the series circuit: R_total = R1 + R2 = 4ฮฉ + 6ฮฉ = 10ฮฉ. Then, use Ohm's Law (I = V/R) to find the current: I = 12V / 10ฮฉ = 1.2 A.
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Electricity and Magnetism โ NECO (Nigeria) NECO Physics Practice Questions Online
This page contains 129 practice MCQs for the chapter Electricity and Magnetism in NECO (Nigeria) NECO Physics. The questions are organized by difficulty โ 28 easy, 79 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.