Asolid metal ball and a hollow plastic ball of the same external radius are released from rest in a large vacuum chamber. when each has fallen 1m, they both have the same 1.inertia.2.change in potential energy.3.momentum.4.kinetic energy.5.speed

5. Speed

Explanation:

Any object in free fall in a vacuum has the same acceleration towards the ground, called acceleration of gravity:

g = 9.8 m/s^2

This means that the speed of an object in free-fall is always given by the equation

v = u +gt (1)

where u is the initial speed and t is the time.

In this case, both balls start from rest (u=0). Since they have same acceleration, they will cover the same distance, 1 m, in the same time t: this means that according to (1), they will also have same speed.

All the other options listed are wrong since they all depend on the mass of the object, and in this case the two objects have different mass.

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.