Electromagnetic...

An athlete with 3m long iron rod in hand runs towards east with a speed of 30 kmph. The horizontal component of earth's magnetic field is $$4 \times 10^{-5} Wb/m^2$$. If he runs with the rod in horizontal and vertical positions then the induced emf generated in the rod in two cases will be

When a coil of cross-sectional area $$A$$ and number of turns $$N$$ is rotated in a uniform magnetic field $$B$$ with angular velocity $$\omega$$, then the maximum emf induced in the coil will be

The resistance coils in a resistance box are made of double folded wire so that their

A conducting rod of length L is falling with velocity V in a uniform horizontal magnetic field B normal to the rod. The induced emf between the ends the rod will be :

A millivoltmeter is connected in parallel to an axle of the train running with a speed of 180 km/hour. If the vertical component of earth's magnetic field is $$0.2 \times 10^{-4} Wb/m^2$$ and the distance between the rails is 1m, then the reading of voltmeter will be :

The coefficients of self induction of two coils are $$L_1 = $$ 8mH and $$L_2=$$ 2mH respectively. The current rises in the two coils at the same rate. The power given to the two coils at any instant is same. The ratio of induced emf's in the coils will be :

The coefficient of mutual inductance of the two coils is $$5H$$. The current through the primary coil is reduced to zero value from $$3 A$$ in $$1 $$millisecond. The induced emf in the secondary coils is

The number of turns in a coil of wire of fixed radius is 600 and its self inductance is 108 mH. The self inductance of a coil of 500 turns will be :

The magnetic flux linked with a coil is $$\phi \leq 8t^2 +3t + 5$$ Weber. The induced emf in fourth second will be

The distance between the ends of the wings of an airplane is $$50 m$$. It is flying in a horizontal plane at a speed of $$360 Km/hour$$. The vertical component of earth's magnetic field at that place is $$2.0 \times 10^{-4} Wb/m^2$$, then the potential difference induced between the ends of the wings will be