a) Cumulus is 100% the correct answer
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 
Answer: force = mass x accelegation
Explanation: 15x3 = 45 N
You have to add 1.7 and 2.2 together!
1.7+2.2=3.9μF
You can find the emf of the battery by using:
Q = CV.
Q = Charge in capacitor plates = 30μC
C = Capacitance of the capacitor = 30μF
V = Q/C = 30/30 = 1V
Ans: The emf of the battery = 1V.