Answer:
Ultraviolet rays from sun are very harmful from skin and can cause sunburn and skin diseases especially ultraviolet B rays.<em> A sunscreen lotion act as a protection barrier on the skin that restrict the direct contact of UV rays with skin and filter the harmful rays to enter the skin. </em>
Radiotherapy is a medical therapy use to treat cancer. <em>Radiotherapy commonly uses x-rays and gamma rays because they are high-energy particles or waves that kills or destroys the cancer cells.</em>
Answer:
This equation is based on twin paradox - a phenomena where one of the twin travels to space at a speed close to speed of light and the other remains on earth. the twin from the space on return discovers that the one on earth age faster.
Solution:
= 10 years
v = 0.8c
c = speed of light in vacuum
The problem can be solved by time dilation equation:
(1)
where,
t = time observed from a different inertial frame
Now, using eqn (1), we get:

t = 16.67 years
The age of the twin on spaceship according to the one on earth = 25+16.67 =41.66 years
100 meters in 9.92 seconds,
=distance/time
=100m/9.92s
=10.0806 m/s
While refrigerant 410a is a near azeotropic refrigerant, it is still best when charging to remove the r-410a as a liquid from the storage cylinder.
Azeotrope means a constant boiling mixture. it is a mixture of two or more liquids,by simple distillation whose proportions cannot be changed. A mixture behaving purely is azeotropic and the mixture which behave differently is called non-azeotropic.