The answer is b hope this helps
One of the efficient concepts that can help us find the number of turns of the cable is through the concept of induced voltage or electromotive force given by Faraday's law. The electromotive force or emf can be described as,

Where,
N = Number of loops
B = Magnetic Field
A = Cross-sectional Area
= Angular velocity
Re-arrange to find N,

Our values are given as,




Replacing at our equation we have:



Therefore the number of loops of wire should be wound on the square armature is 32 loops
It would mean that you could not know the precise volume of the sand. Only the volume of the sand plus the water that was making it damp.
In the experiments listed, the effects are easy to deduce by understanding that the water in the sand adds volume to the 'sample' being measured.
So in the case of calculating air space you would calculate <em>less</em> air space.
Answer:
nothing travels faster than light
Example:
You’ll always see lightning before you hear it, because typically lightning will be a mile away, two miles away.