Answer:
A, The water moving away
Explanation:
When the pebble hits the water the surface tension breaks causing the water to separate away and make a ripple in the water.
Drift velocity is equal to displacement of the moving object per unit time. The SI unit for displacement is meters while that of time is second. Hence the derived SI unit of velocity is meter per second. This also applies to electron mobility which relates to the displacement per unit time of a moving electron
Answer:

where E = electric field intensity
Explanation:
As we know that plastic ball is suspended by a string which makes 30 degree angle with the vertical
So here force due to electrostatic force on the charged ball is in horizontal direction along the direction of electric field
while weight of the ball is vertically downwards
so here we have


since string makes 30 degree angle with the vertical so we will have





where E = electric field intensity
Well I don't know. Let's actually LOOK at the picture and see if that helps.
A, B, C, and D all have the same TOTAL length, but A has the most waves crammed into that same total length.
By golly, that means the length of <u><em>each</em></u> wave in A must be shorter than each wave in B, C, or D.
The correct choice is <em> A </em>. Looking at the picture did the trick !