Answer:
The value is 
Explanation:
From the question we are told that
The first amplitude of the wave is 
The first depth is 
The second amplitude is
The second depth is 
Generally from the spatial wave equation we have

=> 
So considering the ratio of the equation for the two depth

=> 
=> 
=> 
The graph between the strength of the magnet(number of paper clips picked) and battery is approximately a straight line.
For 25 coil, with increase of 1.5 V battery voltage, the electromagnet picks about 5 more clips. So, for a 7.5 V battery, it would pick about 30 paper clips.
For 50 coil, with increase of 1.5 V battery voltage, the electromagnet picks about 15 more clips. So, for a 7.5 V battery, it would pick about 30 paper clips.
The buoyant force on any object acts in the direction opposite to the force of gravity. <em>(A)</em>