Answer:
The energy of photon, 
Explanation:
It is given that,
Voltage of anode, 
We need to find the maximum energy of the photon of the x- ray radiation. The energy required to raise an electron through one volt is called electron volt.

e is charge of electron


So, the maximum energy of the x- ray radiation is
. Hence, this is the required solution.
Answer:
The top of the mountian is colder
Explanation:
As air rises, the pressure decreases. It is this lower pressure at higher altitudes that causes the temperature to be colder on top of a mountain than at sea level.
The best answer is
C) reflecting telescope, because it can be made large enough to gather more radiations (or light) from distant objects.
Reflecting telescopes, unlike refracting telescopes, can be made larger and larger to collect more light, with more precision, from larger distances. Refracting telescopes generally are not used for any demanding purposes, such viewing objects in space by professional astronomers.