Answer:
option C
Explanation:
The correct answer is option C
A light that transmits through n₂ travels t distance before reflection off the n₁ medium and again travels distance t before reaching the point from where it entered n₂ medium. Hence it travels 2 t distance more than the light that is reflected off n₂.
It( light entering n₂) also travels an additional distance equal to, half of the wavelength, when reflected off n₁ ( as n₁ is greater than n₂).
Wavelength in n₂ is = 
Hence, path length difference = 
I think the correct answer from the choices listed above is option B. When calculating the power bill, power companies use kilowatt-hours. This unit is a derived unit of energy equal to 3.6 MJ. If energy is being transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt-hours is the product of the power in kilowatts and the time.
The speed of a electron that is accelerated from rest through an electric potential difference of 120 V is 
<h3>
How to calculate the speed of the electron?</h3>
We know, that the energy of the system is always conserved.
Using the Law of Conservation of energy,
U=0
Here, K is the kinetic energy and U is the potential energy.
Now, substituting the formula of U and K, we get:
=0------(1)
Here,
m is the mass of the electron
v is the speed of the electron
q is the charge on the electron
V is the potential difference
Let 
and 
represent the final and initial speed.
Here, =0
Solving for , we get:
=6.49
m/s
To learn more about the conservation of energy, refer to:
brainly.com/question/2137260
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Yes it is valid all the times under the consideration of acceleration due to gravity .it is not valid on space where there is no influence of gravity
