Answer:

Explanation:
The expression which represent the first diffraction minima by a circular aperture is given by
--------eqn 1
The angle through which the first minima is diffracted is given by
---------eqn 2
As
is very small so we can write 
So from eqn 1 and eqn 2 we can write
--------eqn 3
Here
is the position of first maxima D is the distance of screen from the circular aperture d is the diameter of aperture
It is given that diameter of circular aperture is 14.7 cm so 
Now putting all these value in eqn 3


Explanation:
Force is applied to lift a body against the force of gravity. Example: If an object is lifted to a certain height (h)
Stars are made of very hot gas. This gas is mostly hydrogen and helium, which are the two lightest elements, star is in a delicate and fragile balance between gravity, which would collapse the star to a point, and its internal pressure caused by the energy of the nuclear fusion reaction in the core. When a star's fuel has been spent, it explodes into a giant fireball known as a supernova.. I really hope this helps!!!!
Answer:
1. Primary or P waves are push and pull waves
2. Secondary, S or Shear Waves are also called transverse wave
3. L or surface waves reach the earth's surface after P and S waves
Answer:
1- b: 2- a : 3- c : 4- d
Explanation:
it starts 2 move away from strting point, then no motion, then moves toward the start, the slows up.