Question

2 and 3 plz plz plz plz plz plz ​

Answer 1

Hi........

Second Question.

 Energy from oceans is used as tidal energy, wave energy, and thermal energy. 

OTEC (Ocean Thermal Energy Conversion) power plants are devices used to harness ocean thermal energy. 

In OTEC system, the warm surface water is used to boil a liquid like ammonia or CFC. The vapour of the liquid is then used to drive turbine of generator. The cold water from the ocean depths is pumped up to convert the vapour again into liquid.

Third Question

(a) When a bar magnet is pushed into the coil of insulated copper wire connected to a galvanometer, an induced current is set-up in the coil due to change of magnetic field through it. As a result, galvanometer gives a deflection (say towards left).

(b)  When the bar magnet is withdrawn from inside the coil, again an induced current is set­up in the coil due to change of magnetic field through it. As a result galvanometer gives a deflection in the reverse direction. (say towards right).

(c)  If the bar magnet is held stationary inside the coil, then there is no induced current in the coil, because there is no change in magnetic field through it. As a result, galvanometer does not show any deflection.                                                                                                

(ii) This Phenomenon is called Electro-Magnetic Induction.