Answer:

Explanation:
Given data:
L =2.00 *10^4 m
d = 18*10^4 m
M = 18 *10^6 kg
m_1 = 8*10^6 kg
Gravitational energy is given as

mass per unit length is given as

calculating potential energy







Answer:
advantage : 1) produce no polluting gases .
2)doesn't contribute to global warming .
disadvantage: 1)waste is radioactive and safe disposal is very difficult and expensive.
2)local thermal pollution from east water affects marine life
Answer:
The brilliant galaxy centers are known as quasars. According to the astronomers quasars exists at the center o galaxies and in the center of galaxies there exists the black holes. Quasars are known as the brightest objects of the universe and they appear like a star in the telescopes.
Explanation:
Answer:
Intensity, 
Explanation:
Power of the light bulb, P = 40 W
Distance from screen, r = 1.7 m
Let I is the intensity of light incident on the screen. The power acting per unit area is called the intensity of the light. Its formula is given by :




So, the intensity of light is
.