The rubber protects him from being electrocuted by the flow of current going through the plug.
Hope this helped!!
Answer:
C. Quadruple the intensity
Explanation:
The intensity of the sound is proportional to square of amplitude of the sound.
I ∝ A²

When the given sound is twice loud as the initial value, then the new amplitude is twice the former.
A₂ = 2A₁

Thus, to make a given sound seem twice as loud, the musician should Quadruple the intensity
Place the boxes 10cm apart, if they are closer that concentrates the mass of the boxes more