Voltage = N * Δ(BA)/Δt
<span>BA = 0.57*0.16*0.22 = 2.0064e-2 </span>
<span>N = 505 </span>
<span>115/505 = Δ(BA)/Δt = 23/101 </span>
<span>When the top of the coil rotates to the bottom (1/2 half cycle) BA changes from max to min and when the bottom rotates back to the top BA changes from min to max. So Δ(BA) is twice per cycle </span>
<span>So 2*101Δ(BA)=23Δt and Δt = 1/f </span>
<span>202*2.0064e-2/23 =Δt = 1/f => f =5.675Hz</span>
Answer:Increase by a factor of 25
Explanation:
We know that magnetic force is proportional to 
where r is the distance between them
Thus 
Where 
=magnetic field
If distance is reduced by a factor of 
then force must increase by a factor of 
because
so 
The answer is true
Hope its help;)
