General Knowledge - Basic General Knowledge - Discussion

Exposure to sunlight helps a person improve his health because the ultraviolet rays convert skin oil into Vitamin D.

Sun light includes many type of radiations such that gamma rays, x-rays, ultra Violet rays, light rays, infrared rays, micro waves, radio waves, here gamma rays, x-rays, UV rays are much more harmful of certain wavelength, but these gamma and x-rays are filtered ozone layer, by a some chemical reaction called ozone filtration action, but UV rays of certain wavelength (which are harmful) are gets filtered, then remaining UV rays of less harmful wavelength rays are reaches the Earth, also up to morning 10:40 AM the harmful effect is zero (proved) on living things, so before that time those rays are touches the skin of animals, so the water content and Melanin oil content which is secreted by Mitochondria (called the power house of cell) in cells on skin under goes chemical reaction in the skin cells using UV rays boost the rate of reaction so that it gives energy, Vitamin-D, and water along with some urea (nitrogen content) and that water along with urea come out from the body as a waste, in this way UV rays helps our body in converting into Vit-D.

Thank you @Ankit.

How is vitamin D useful for us if we are not consuming it? UV rays are converting skin oil into vitamin D (hopefully accepted) still how these vitamin D is useful unless we are not using it?

UVB :

(a) UVB has a wavelength range from 290 nm to 320 nm.
(b) Because its wavelength is shorter than UVA it cannot pass through window glass.
(c) it causes tanning and is roughly 1000 times more likely than UVA to cause sunburn.
(d) However, it does helps the body with normal vitamin D production.
(e) the ozone layer is very effective at screening out UVB. For radiation with a wavelength of 290 nm, the intensity at Earth's surface is 350 million times weaker than at the top of the atmosphere.
(f) unlike UVA the intensity of UVB reaching the Earth's surface varies with the season. It is more intense in the summer than in the winter.
(g) its intensity varies with weather conditions and the time of day. It is more intense at midday than in the morning or late afternoon.
(h) it is also more intense at high altitudes and near the equator.
(i) it is known to be an important factor in the development of cataracts and the growth of 90% of skin cancers.
(j) you can protect yourself against the effects of UVB by using sunscreens containing a sun protection factor.

What about body oil?

Harmfull ultraviolet rays are blocked by ozone. Rest are bound to come on earth.

And skin oil is some form of saturated fat which works as solute for vitamin D on skin and help in absorbng by the body.

If UV rays are good for providing vitamin D then why ozone layer is there to trap them down?

According to me, C is the correct answer.

Uv rays are harmful but in winter we bask the sun. It is the good source of vitamin d. Bask the sun for vitamin d is not harmful because we only use in winter. Other sources of vitamin D are an egg.