Question

A solenoid of diameter 4 cm, length 50 cm consists of 2000 turns. calculate its self inductance.

Answer 1

length AB=200m=2R

time taken to complete one round=40 sec

let the starting point be A

in 140 sec or 2 min 20 sec number of rounds completed=14040=3.514040=3.5

distance traveled=3.5 * (2*ππ*R)=3.5*2*ππ*100 m=2200 m (approx)

displacement refers to change in position from the starting point.the final point is B

as after 3.5 revolutions(starting from A) the athlete will be at B.

displacement=200m