Q1. If the resistance of a circuit is 10 ohms and the induced EMF is 5 V, what is the induced current? (2022)
Solution:
Using Ohm's law, I = V/R = 5 V / 10 ohms = 0.5 A.
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Q2. A coil of wire has 100 turns and is placed in a magnetic field of strength 0.5 T. If the area of the coil is 0.1 m² and the magnetic field is perpendicular to the coil, what is the magnetic flux through the coil? (2022)
Solution:
Magnetic flux (Φ) = B × A × cos(θ). Here, B = 0.5 T, A = 0.1 m², and θ = 0° (cos(0) = 1). Thus, Φ = 0.5 T × 0.1 m² × 1 = 0.05 Wb.
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Q3. If a magnetic field is increasing at a rate of 0.1 T/s, what is the induced EMF in a coil of 50 turns and area 0.2 m²? (2021)
Solution:
Induced EMF (ε) = -N * (dB/dt) * A = -50 * 0.1 T/s * 0.2 m² = -1 V.
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Q4. In a generator, what is the role of the rotating coil? (2022)
Solution:
In a generator, the rotating coil induces EMF by changing the magnetic flux through it.
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Q5. A coil with 100 turns has a magnetic flux of 0.02 Wb passing through it. If the flux changes to 0.01 Wb in 2 seconds, what is the induced EMF? (2022)
Q6. If the area of a coil is doubled while keeping the magnetic field constant, what happens to the magnetic flux through the coil? (2023)
Solution:
Magnetic flux (Φ) is given by the product of magnetic field (B) and area (A). If the area is doubled and the magnetic field remains constant, the magnetic flux also doubles.
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Q7. A changing magnetic field induces an electric field. This phenomenon is described by which of the following laws?
Solution:
The phenomenon of a changing magnetic field inducing an electric field is described by Faraday's law of induction.
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Q8. A loop of wire is placed in a uniform magnetic field. If the magnetic field is increased uniformly, what happens to the induced current in the loop?
Solution:
According to Faraday's law, an increase in magnetic field through the loop induces a current in the loop, which increases as the rate of change of magnetic flux increases.
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Q9. A loop of wire is placed in a uniform magnetic field. If the field strength is increased, what happens to the induced current? (2023)
Solution:
If the magnetic field strength increases, the magnetic flux through the loop increases, inducing a current according to Faraday's law.
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Q10. If the magnetic flux through a coil changes from 0.2 Wb to 0.5 Wb in 2 seconds, what is the average induced EMF? (2021)
Solution:
Average induced EMF = -ΔΦ/Δt = -(0.5 Wb - 0.2 Wb) / 2 s = -0.15 Wb/s = 150 V.
