In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. Which of the following statements is true regarding this process?
A. The gas must absorb heat from its surroundings.
B. The gas must release heat to its surroundings.
C. The pressure of the gas also stays constant.
D. The process is adiabatic.

B. The gas must release heat to its surroundings.

Explanation:

Since the process is reversible , it must be slow . Since temperature is kept constant so the internal energy is constant , Since volume is decreased , pressure must be increased. Since work is done on the gas ( gas is compressed )  , so heat must be released by the gas so that its internal energy remains constant.

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.

96.77 amp

explanation:

rl = 250/100 = 2.5 ohms.

egl = 250 + (100 × 0.1) + 2 = 262 v.

at 700 r.p.m., eg2 = 262 × 700/1000 = 183.4 v.

if ia is the new current, then eg2 - 2 - (ia × 0.1) = 2.5 ia

which means this will give ia = 96.77 amp.