A transformer has 500 turns of the primary winding and 10 turns of the secondary winding. a) Determine the secondary voltage if the secondary circuit is open and the primary voltage is 120 V

First we use the fact that the ratio of the voltage on the secondary and on the primary will be the same as the ratio of the number of turns of both coils,

u=u^2/U^1 = N^2/N^1

we evaluate the unkown secondary voltage

u^ 2=N^2/N^1 u1

We substitute the given values -

u^2= 10/500 * 120v = 2.4v

Hence, the answer is 2.4v.

1 a

2 b

3 b

4 d

5 d

6 d

explanation:

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.