OK so yeah the mercury Venus Earth and Mars a rocky planets and Jupiter Saturn Uranus and Neptune our gaseous planets so I think that’s your answer correct me if I’m wrong:D
I’m not 100% sure but i think it’s A because if you divide the speed by the time you get 2 and also all the other answer choices don’t make any sense!
One side of the wave changes speed before the other side, causing the wave to move
Answer:

Explanation:
Given that
For straight wire
Charge density= λ
For hollow metal cylinder
Charge density=2 λ
We know that electric filed for wire given as


Now the electric filed due to hollow metal cylinder


Now by considering the Gaussian surface r<R then only electric fild due to wire will present.So
At r<R
