Answer:

Explanation:
Given that
Length= 2L
Linear charge density=λ
Distance= d
K=1/(4πε)
The electric field at point P



So

Now by integrating above equation

If the bubble travels 10 meters per second and it takes 10 seconds, then just multiply the distance per second by the total seconds to get the total depth.
10 • 10 = 100
The lake is 100 meters deep.
Think of it this way to clarify the answer:
It takes a bubble traveling at a speed of 10 meters per second 10 seconds to travel 100 meters.
Answer:
The value is
Explanation:
From the question we are told that
The amount of power delivered is 
The time taken is 
The wavelength is 
Generally the energy delivered is mathematically represented as

Where
is the Planck's constant with value 
c is the speed of light with value 
So

=> 