The value of the second charge is 1.2 nC.
<h3>
Electric potential</h3>
The work done in moving the charge from infinity to the given position is calculated as follows;
W = Eq₂
E = W/q₂
<h3>Magnitude of second charge</h3>
The magnitude of the second charge is determined by applying Coulomb's law.

Thus, the value of the second charge is 1.2 nC.
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All the boats operating at night requires Navigation light.
Navigation light helps prevent collisions between boats and see if visibility is poor. The types of boat are : Rowboats, Tug boats, Vessels, Sailboat etc.
Various boats have different lightning color to show its use and side of the boat.
Answer:
The moon has no atmosphere
Explanation:
The temperatures on the surface of the Moon vary much more than those on Earth because the moon has no atmosphere (third answer in the list), and therefore there are no molecules that could retain residual heat and make the change from day to night a softer transition.
The refractive index of water is

. This means that the speed of the light in the water is:

The relationship between frequency f and wavelength

of a wave is given by:

where v is the speed of the wave in the medium. The frequency of the light does not change when it moves from one medium to the other one, so we can compute the ratio between the wavelength of the light in water

to that in air

as

where v is the speed of light in water and c is the speed of light in air. Re-arranging this formula and by using

, we find

which is the wavelength of light in water.