Answer: Waning
Explanation: Not much explanation for this
Answer:
Nitrogen and oxygen are by far the most common; dry air is composed of about 78% nitrogen (N2) and about 21% oxygen (O2). Argon, carbon dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases.
Answer:

Explanation:
The energy of a photon is given by:

where
h is the Planck constant
c is the speed of light
is the wavelength of the photon
In this problem, we have a microwave photon with wavelength

Substituting into the equation, we find its energy:

Answer:
Option (b) is correct.
Explanation:
Elastic collision is defined as a collision where the kinetic energy of the system remains same. Both linear momentum and kinetic energy are conserved in case of an elastic collision.
Inelastic collision is defined as a collision where kinetic energy of the system is not conserved whereas the linear momentum is conserved. This loss of kinetic energy may due to the conversion to thermal energy or sound energy or may be due to the deformation of the materials colliding with each other.
As given in the problem, before the collision, total momentum of the system is
and the kinetic energy is
. After the collision, the total momentum of the system is
, but the kinetic energy is reduced to
. So some amount of kinetic energy is lost during the collision.
Therefor the situation describes an inelastic collision (and it could NOT be elastic).