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Questions
A horizontal straight wire 10 m long extending from east to west is falling with a speed of 5.0 m s−1, at right angles to the horizontal component of the earth’s magnetic field, 0.30 × 10−4 Wb m−2.
- What is the instantaneous value of the emf induced in the wire?
- What is the direction of the emf?
- Which end of the wire is at the higher electrical potential?
A horizontal conducting rod 10 m long extending from east to west is falling with a speed 5.0 ms–1 at right angles to the horizontal component of the Earth's magnetic field, 0.3 × 10–4 Wb m–2. Find the instantaneous value of the emf induced in the rod.
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Solution
Length of the wire, l = 10 m
Falling speed of the wire, v = 5.0 m/s
Magnetic field strength, B = 0.3 × 10–4 Wb m–2
- Emf induced in the wire,
e = Blv
= 0.3 × 10–4 × 5 × 10
= 1.5 × 10–3 V - Using Fleming’s right-hand rule, it can be inferred that the direction of the induced emf is from West to East.
- The eastern end of the wire is at a higher potential.
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