Answer:
B
Explanation:
the amplitude is the distance from the resting point to the crest/trough.
Answer:
3.85*10^8m
Explanation:
We know that
Speed v = distance/time t
So distance = v x t
So = 3*10^8 x 2.56s
= distatance = 7.7*10^8m
However this is double the distance from the earth to the moon, so to get distance from earth to the moon we divide by 2
7.7*10^8/2= 3.85*10^8m
Answer:
emf will also be 10 times less as compared to when it has fallen 
Explanation:
We know, from faraday's law-

and 
So, as the height increases the velocity with which it will cross the ring will also increase. 
Given


Now, from 

From equation a and b we see that velocity when dropped from
is 10 times greater when height is 40
so, emf will also be 10 times less as compared to when it has fallen 