NEET
Practice Test 7
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A conductor of length 0.4 m is moving with a speed of 7 m/s perpendicular to a magnetic field of intensity 0.9 Wb/m2. The induced e.m.f. across the conductor is

  • Solution

    Length of conductor (l) =0.4 m; Speed (v) =7 m/s and magnetic field (B) = 0.9 Wb/ m2. Induced e.m.f.

    (ε) = Blv cos q = 0.9 × 0.4 × 7 × cos 0º = 2.52 V.

A horizontal telegraph wire 0.5km long running east and west in a part of a circuit whose resistance is 2.5Ω. The wire falls to g= 10.0 m/s2 and B= 2 × 10–5 weber/m2, then the current induced in the circuit is

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In an AC generator, a coil with N turns, all of the same are aA and total resistance R, rotates with frequency ω in a magnetic field B. The maximum value of emf generated in the coil is

  • Solution

Which of the following units denotes the dimension \(\frac{ML^{2}}{Q^{2}}\),where Q denotes the electric charge?

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If coefficient of self induction of a coil is 1 H, an e.m.f. of 1V is induced, if

  • Solution

    From e =LdI / dt, dI / dt = e⁄L = 1⁄1 = 1 As-1

The mutual inductance between two coils depends on

  • Solution

    Mutual inductance between two coils depends on all the three factors given here.

The back e.m.f. in a d.c. motor is maximum, when

  • Solution

    The back e.m.f.in a motor is induced e.m.f., which is maximum, when speed of rotation of the coil is maximum.

Two solenoids of same cross-sectional area have their lengths and number of turns inratio of 1 : 2. The ratio of self-inductance of two solenoids is

  • Solution

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ELECTROMAGNETIC INDUCTION
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