Q1. 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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Q2. 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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Q3. The direction of induced current can be determined by which law? (2023)
Solution:
Lenz's Law states that the direction of induced current is such that it opposes the change in magnetic flux that produced it.
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Q4. If the area of a loop in a magnetic field is doubled while keeping the magnetic field strength constant, what happens to the magnetic flux through the loop?
Solution:
Magnetic flux (Φ) is given by Φ = B * A. If the area (A) is doubled and the magnetic field (B) remains constant, the magnetic flux also doubles.
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Q5. A transformer has 200 turns in the primary coil and 50 turns in the secondary coil. If the primary voltage is 240 V, what is the secondary voltage? (2023)
Solution:
Using the transformer equation Vp/Vs = Np/Ns, we find Vs = Vp × (Ns/Np) = 240 V × (50/200) = 60 V.
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Q6. 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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Q7. In a generator, mechanical energy is converted into electrical energy through: (2019)
Solution:
In a generator, mechanical energy is converted into electrical energy through the process of electromagnetic induction.
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Q8. A loop of wire is moved into a magnetic field at a constant speed. What happens to the induced current as the loop enters the magnetic field? (2023)
Solution:
As the loop enters the magnetic field, the change in magnetic flux increases, leading to an increase in the induced current.
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Q9. According to Faraday's law of electromagnetic induction, the induced EMF in a circuit is proportional to the rate of change of which of the following? (2020)
Solution:
Faraday's law states that the induced EMF in a circuit is directly proportional to the rate of change of magnetic flux through the circuit.
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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.
