The answer is C. Substance Y has the highest temperature because its particles have more kinetic energy.
The frequency of the wheel is given by:

where N is the number of revolutions and t is the time taken. By using N=100 and t=10 s, we find the frequency of the wheel:

And now we can find the angular speed of the wheel, which is related to the frequency by:
Magnetic field is proportional to NIA.
N is the number of turns, I is the current and A is the area
You see N=2n, I = 3 i. Therefore, it will 6 times stronger
200*6= 1200 kg. It can lift now is 1200 kg.
Answer: time is the same
Explanation: the distance(H) is the same in each case .
we drop the balls , no drag force using basic kimnematics
y =gt*t/2 , yo=0 , vo=0 , y=H , so : t= sqrt(2H/g)
comment: if distance H starts to grow....we could begin to note a difference because of gravity g is smaller as we go up