(i) State Faraday's law of electromagnetic induction.
(ii) A jet plane is travelling towards west at a speed of 1800 km/h. What is the voltage difference developed between the ends of the wing having a span of 25 m, if the Earth's magnetic field at the location has a magnitude of `5xx10^(-4) T` and the dip angle is `30^(@)` ?

Explanation

(i) Faraday's law of electromagnetic inducation :
1. Whenever magnetic flux linked with a circuit changes, induced e.m.f. is produced.
2. The induced e.m.f. lasts as long as the change in the magnetic flux continues.
3. The magnitude of the induced e.m.f. directly proportional to the rate of change of the magnetic flux linked with the circuit. i.e,
`e=(d phi)/(d x)`
(ii) `u=1800" km h"=(1800xx1000)/(60xx60)=500 m//s`
`delta=30^(@), H=5xx10^(-4) T`
`V=H tan delta`
`=5x10^(-4)xxtan 30^(@)`
`=5xx10^(-4) xx 1/sqrt(3)=4/sqrt(3) xx10^(-4) T`.