Answer:
The coefficient of thermal expansion of material B is more than A
Explanation:
As we know that when we apply heat to a material it expands. The amount of expansion depends on the nature of the material. The amount of expansion depends on the coefficient of thermal expansion of the material.
If a material has high value of thermal expansion coefficient then it expands more.
here material A expands less and material B expands more because the pin which is made by material A becomes loosen, so the coefficient of thermal expansion of B is more than the coefficient of thermal expansion of A
Comets are like "dirty snowballs"; frozen gasses with dust and rocks in them. Each pass near the Sun causes the comet's nucleus to be exposed to intense sunlight, which causes some tiny fraction of the gas to evaporate and carry some of the dust and rock away into space. The gas and dust, near the Sun, cause the comet's "tail", and repeated passes cause dust and rock to spread out along most of the orbit of a comet. When the Earth enters one of these trails of old comet dust, we have meteor showers.
<span>On rare occasions, comets break apart or even more rarely, crash into planets. In 1994, the comet Shoemaker-Levy 9 broke apart and then collided with the planet Jupiter.</span>
Land surfaces change, erosion happens, the ground collapses, etc.
Answer:

Explanation:
By Snell's law we know at the left surface




now we have


now on the other surface we know that
angle of incidence = 

so again we have

so we have


also we know that


By solving above equation we have
