Interferometry (Multiple Choice)

Answer to q. 1

a

Answer to q. 2

Photons in the core are gamma rays. Each time a gamma ray encounters electrons or nuclei it is deflected in a random direction, and slowly drifts outward toward the surface while being converted into several photons of lower energy. The inner parts of the Sun where this net outward motion of energy in the form of radiation occurs is called the radiative zone. Photons eventually reach the outer layers of the Sun which is not very transparent to radiation. Here the energy goes into convection, and this region is known as the convective zone. Energy is carried outward as circulating gas, not as photons. When the energy finally reaches the photosphere, after perhaps millions of years, it is radiated into space as photons of visible light.

Answer to q. 3

e

Answer to q. 4

(1) Gravity: The attractive force between masses.
(2) Electromagnetic force (Coulomb force): The force between charged objects, can be either attractive or repulsive.
(3) Weak force: Involved in the radioactive decay of certain kinds of nuclear particles.
(4) Strong force: Binds together atomic nuclei.
The strong force and the weak force are short-range forces that are effective only within the nuclei of atoms.