General Knowledge - Basic General Knowledge - Discussion


Exposure to sunlight helps a person improve his health because

[A]. the infrared light kills bacteria in the body
[B]. resistance power increases
[C]. the pigment cells in the skin get stimulated and produce a healthy tan
[D]. the ultraviolet rays convert skin oil into Vitamin D

Answer: Option D


No answer description available for this question.

Raji said: (Jan 10, 2011)  
What are skin oils?can anybody explain this please?

Babu said: (Feb 7, 2011)  
Very small amount of ultra violet rays are incident along with normal light rays on the human body which helps convert the skin oil into vitamin D.

Anish said: (Feb 14, 2011)  
Ultra violet rays are absorbed by Ozone layer, then how could it comes to skin.

Lokesh Bhirud said: (Feb 16, 2011)  
Can anybody tell the exact reason for this answer. It was really tricky.

Siva said: (Feb 27, 2011)  
Not direct UV rays strike the skin. The filtered UV rays from ozone, which are non destructive indulge in this process.


Skin oils are nothing but white lipid substance beneath our skin.

Akanksha said: (Mar 1, 2011)  
UV rays are harmfull for human body then how can they help us?

There is a hole in the ozone layer.

Ruchitha said: (May 26, 2011)  
Can you explain about ozone layer ?

Ravi said: (May 31, 2011)  
Ozone layer is the protective layer. Its chemical composition is O3. It absorb ultra violet ray, which is very harmful for us. But now a day, due to heavy pollution layer become destroy. The main harmful gass is carbon-mono-oxide, chloro-fluro-carbon.

Amar said: (Jun 19, 2011)  
Ozone layer either pass uv rays or stop them. Whats the meaning of filtered uv rays. Sunlight is filtered no doudt through ozone. Moreover uv rays are of short wavelength, if it penetrate in skin, it would cause skin cancer or may cause mutation in cells. Sunlight stimulate the formation of melanin pigment in the skin layers. Which is helpful in maintaining homeostasis of body.

Siri said: (Jul 21, 2011)  
Can you tell me the effect of UV radiations ?

Ankit Dwivedi said: (Jul 23, 2011)  
If you will read deeply about ultraviolet radiations. Then you will found that only harmful radiations are harmfull for our body. Actualy ultraviloet radiations are of two types. And their harmfullness depends on their intensity and frquency. So only harful radiations of that are absorbes by ozone layer. And reaching part of it convert oil of skin into vitamin D.

Sandeep said: (Aug 2, 2011)  
So what happened if we absorb more and more uv in our body, such it will fall normally in our body, it is not harmful for skin which causes skin cancer?

Kiran said: (Aug 22, 2011)  
Then you get suffer from skin cancer or any other dangers like skin-burn.

Yoga, said: (Aug 23, 2011)  
Vitamin D is a group of fat-soluble secosteroids. In humans Vitamin D is unique both because it functions as a prohormone and because when sun exposure is adequate the body can synthesize it (as Vitamin D3). Measures of the serum levels reflect endogenous synthesis from sun exposure as well as intake from the diet and it is believed that synthesis may contribute generally to the maintenance of adequate serum concentrations. The evidence indicates that the synthesis of vitamin D from sun exposure works in a feedback loop that prevents toxicity but, because of uncertainty about the cancer risk from sunlight, no recommendations are issued by the Institute of Medicine for the amount of sun exposure required to meet vitamin D requirements.

Lingesha said: (Sep 19, 2011)  
I'm also not confirm in this. After reading these informations I come to the following decision.

There are two types of UV rays. And it depends on the uv rays intensity and frequncy. But very harmful UV radiations are absorbed by ozone layer. And transferred radiations may convert that skin oil into vitamin D on the human body.

Arun said: (Sep 23, 2011)  
But the uv rays causes the cancer to the human bodys then how can be it increases vitamin D.

Gargi said: (Oct 1, 2011)  
UV rays are not responsible fo vitamin d, the sunlight which we get in morning from 8 to 10 am gives the vitamin d and it keeps us away from skin diseases, the sunlight from 11 to 3 pm is very harmful to skin, we should avoid the exposure of our skin in this duration.

Dipika Singh said: (Oct 2, 2011)  
@ arun.

It depends on the frequency of uv rays we are facing, the uv rays which is harmful for us, is absorbed by ozone layer, but as we know, now due to hole in our ozone layer, we have to face the, hazardous effect of it, ie, cancer, as you are saying.

Ram said: (Oct 29, 2011)  
The sunlight improves vitamin D in human body.

Tekram Sahu said: (Nov 16, 2011)  
Vit.D is fat soluble vitamin its chemical name is ergocalciferol (in plant source )& colicalciferol ( Animal source) its also called sunsine vitamin. sun light is most important source of vitamin D, its basically two form vit.D2 & vit.D3. vitamin D consumed with the help of Folic acid & calcium. vitamin D3 help bone &cartilage. if laking of vit D3 caused Rickets disease in baby.

Usha said: (Nov 18, 2011)  
UV rays causes skin cancer also then how can we say that it will help a person to improve his health?

A.M.Vijayan said: (Jan 10, 2012)  
That's correct because of the oil content for vitamin strength that way to help our health.

Muthu said: (Jan 12, 2012)  
A division between an area or areas on the skin of a human of pronounced comparative paleness relative to other areas of their body that have been suntanned by prolonged exposure to ultraviolet radiation.

Avi said: (Jan 19, 2012)  
Not only in the morning, in the evening too we make Vitamin D.

Ashutos said: (Jan 22, 2012)  
In the evening the sun is not present, so how the uv ray is helpfull to our body?

Vanitha said: (Feb 27, 2012)  
I think UV rays are very harmfull then how can it convert into Vitamin D.

I didn't get a pasitive about it. Please, can anybody explain ?

Sagar Dhapodkar said: (May 12, 2012)  
Can you explain the pimples problem and dark circles.

Jeevan said: (May 18, 2012)  
Friends very less amount of UV-rays doesn't affect our cell tissues. So its better to stand out in morning sunlight.

Jeevan said: (May 18, 2012)  
Dark circles doesn't come through sun light to prevent that you have to sleep properly. Don't allow dusts and oil on your face for long time at-least have to wash our face with cold water 6 times in a day and don't use soap more than twice.

Raam : said: (Jul 17, 2012)  
Vitamin D is a fat-soluble vitamin which can provide for the body's needs in one of two ways. Through the action of sunlight on the skin, or through the major food sources of cod liver oil, cold-water fish, butter, and egg yolks. When the sun shines on the skin, the ultraviolet rays activate a form of cholesterol which is present in the skin, converting it to Vitamin D (1). Because the body can provide sufficient Vitamin D to meet its needs simply through exposure to sunlight, some feel it is not really a vitamin, but instead is a hormone.

Arun said: (Oct 17, 2012)  

Actually there are three types of u.v. rays depending upon it's wavelength.. (u.v.A 320-400 NM) & (u.v.B 280-320 NM) & (u.v.C 200-280 NM) actually u.v..c is cut off by ozone layer while we get maximum exposure to u.v.A & u.v.B because it is closer to visible wavelength which we can see with our eyes. rainbow color.

Vitamin D3 is made in the skin with ultraviolet light of UVB type at wavelengths between 270 and 300 nm, with peak synthesis occurring between 295 and 297 nm, which is then converted into active form of Vitamin D which is necessary for body defense mechanism.

The body basically need daily sunlight to produce vitamin d since vitamin cannot be stored in body like fat & proteins.. so daily exposure is necessary in morning.

Aunu said: (Dec 27, 2012)  
Actually, uv rays affects the skin, means skin cancer and other skin diseases. Then how will these rays form vit D very little amount of rays enters atmosphere.

Raj said: (Apr 16, 2013)  
After reading various answer. I reached on this result that UV ray with low frequency are not harmful for us.

Arvind said: (Jul 12, 2013)  
Sunlight means only morning light. Sunlight after morning contains much amount of uv rays which is harmful to body.

Avinash said: (Sep 20, 2013)  
Our skin acts as layer for transmitting sweet. So, when fat or oil can coagulate to these sweet, it makes to absorb these fatty. Black people absorb more light when compare to white.

Alkshendra said: (Sep 20, 2013)  
Ozone layer protect us from the uv rays but in that days in many area like africa, west indies and many other places a hole is found in ozone layer it is affected by air of freeze, by our toothpaste, green house effect and by chlorofluorocarbon are responsible for it.

Joel said: (Sep 22, 2013)  
If we don't have enough vitamin D in our body we may get diseases so the sunlight gives us vitamin D so sunlight is good.

Pankaj K C said: (Nov 12, 2013)  
But in morning the uv is very low in sunlight so it is not harmful. , and only in morning we get Vit. D. Not all over the day.

Sandhya said: (Feb 6, 2014)  
Why only morning sunrays? why not evening sunrays?

Aishwarya said: (Apr 11, 2014)  
Is only at morning in low sunlight we get vitamin D or we get at any time in a day?

Nivi said: (Jun 29, 2014)  
Is we get vitamin D at evening?

Prachi said: (Jul 31, 2014)  
No we don't get vit D in the evening only in morning between seven to ten.

Prajakta said: (Aug 3, 2014)  
Your body is able to produce its own vitamin D3 when your skin is exposed to the sun's ultraviolet rays, specifically ultraviolet (UVB) radiation. When UVB rays hit your skin, a chemical reaction happens: Your body begins the process of converting a prohormone in the skin into vitamin D. In this process, a form of cholesterol called 7-dehydrocholesterol (7-DHC), naturally found in your skin, absorbs the UVB radiation and gets converted into cholecalciferol. Cholecalciferol is the previtamin form of D3. Next, the previtamin travels through your bloodstream to your liver, where the body begins to metabolize it, turning it into hydroxyvitamin D, which is also known as 25-hydroxyvitamin D or 25(OH)D. The kidneys then convert the 25(OH)D into dihydroxyvitamin D, also called 1,25-dihydroxyvitamin D or 25(OH)2D -- this is the hormone form of vitamin D your body can use.

Uthkar Sailu said: (Oct 17, 2014)  
Our bodies manufacture vitamin D when the sun's ultraviolet B (UVB) rays interact with 7-dehydrocholesterol (7-DHC) present in the skin.

"However, we can produce only a limited amount of vitamin D from UVB. A few minutes at midday are sufficient for many Caucasian".

Rory said: (Jan 1, 2015)  
How can vitamins do great duty?

Rory said: (Jan 1, 2015)  
Can anybody answer this what does vitamin D do?

Pankaj said: (Jan 13, 2015)  
Explain the advantage of vitamin D?

Akshra said: (Mar 29, 2015)  
What is the role of vitamins in human body?

Reetika Thakur said: (Jun 21, 2015)  
What are skin oil? Explain.

Jaya said: (Jun 22, 2015)  

Vitamin D symptoms-defective calcification of bones.

Srinivas said: (Jul 22, 2015)  
At-least 2 hrs a day we should expose to sun is the sense.

Malinimadhavan said: (Jul 25, 2015)  
What happens when we apply soap more then twice a day friends? Please explain it.

Chahat said: (Aug 8, 2015)  
Ya ultra violet rays comes from sunlight but first it absorb by ozone which is outer layer of environment.

Ozone layer absorb unwanted or harmless ray from sun and then it comes to environment and absorb by body.

Atul said: (Aug 22, 2015)  
UV radiation causes skin cancer then how can you say it is useful for body?

Marcus Giri said: (Sep 13, 2015)  
UV radiations cannot penetrate through ozone layer, unless and until it gets depleted.

Vrutti said: (Sep 25, 2015)  
But as we have studied earlier that UV rays are bad for us it gives skin diseases like cancer so how that is useful?

Prabhanjan said: (Sep 25, 2015)  
Sunlight convert provitamine D to vitamin D.

Mend inactive form of vitamin to active vitamin which is having many important physiological role.

Atrayee said: (Oct 2, 2015)  
Who is the father of English poetry?

Shubham said: (Oct 16, 2015)  
Can you explain correct and simple answer for this question?

Prashanth said: (Nov 14, 2015)  
Only the rays which are harmless reaches the ground due to ozone layer.

Komal Kodole said: (Dec 18, 2015)  
What is the piezoelectric device?

Pooja said: (Dec 20, 2015)  
What happen if we apply a soap more then twice a day?

Geetha said: (Dec 30, 2015)  
Skin gets aged soon. Actually we should not apply soap instead of that we can apply face wash because it will be diluted.

Gayathri said: (Feb 7, 2016)  
Thank you very useful to me.

M.Abass Sheikh said: (Feb 18, 2016)  
Sunlight helps in the development of vitamin D. So answer is C.

Priya said: (Feb 18, 2016)  
About Second ozone hole?

Apoorv Agrawal said: (Mar 1, 2016)  
It's very surprising to know about how skin oil is converted into vit-D and the chemical reactions associated with it. Can anybody tell me?

Vijay said: (Apr 14, 2016)  
I don't know exactly but I know something about it that UV rays which come from the sun is filtered from ozone. So these UV rays are less harmful. These UV rays are absorbed by the oils present in the skin which converts into vitamin D.

Jamin said: (Jun 4, 2016)  
* UV rays are harmful.
* UV ray causes cancer to ou skin.

Ahmed said: (Jun 12, 2016)  
Sunlight contains UV that is harmful to the body.

So, it does not improve our body.

Sunnysingh said: (Jun 25, 2016)  
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.

Rajnish said: (Jul 6, 2016)  
According to me, C is the correct answer.

Bhushan Mandal said: (Aug 13, 2016)  
If UV rays are good for providing vitamin D then why ozone layer is there to trap them down?

Ram Anuj Gaur said: (Sep 9, 2016)  
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.

Raja Babu said: (Sep 15, 2016)  
What about body oil?

Ankit Manchalwar said: (Apr 20, 2017)  

(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.

Rohit said: (May 10, 2017)  
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?

Manisha Shaik said: (Jul 3, 2017)  
Thank you @Ankit.

Naveen S B said: (Jul 21, 2017)  
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.

Vasanthi said: (Oct 6, 2017)  
Exposure to sunlight helps a person improve his health because the ultraviolet rays convert skin oil into Vitamin D.

Ajay Mehra said: (Oct 19, 2017)  
Thanks @Vasanthi.

Shruthi Raichur said: (Nov 4, 2017)  
That's right answer because, this vitamin very low in (01.00) to me. So please give to me best tips.

Minku Paul said: (Nov 14, 2017)  
In what way are uv rays convert skin oil into vitamin D.

Iswarya said: (Mar 26, 2018)  
What will happen if UV rays are converted into vitamin D?

Hiya Singh said: (Mar 26, 2019)  
Triggers vitamin D " UV from the Sun is needed by our bodies to produce vitamin D. Vitamin D helps strengthen bones, muscles and the body's immune system. It may also lower the risk of getting some kinds of cancers such as colon cancer.

Ganesh said: (Jul 30, 2019)  
Our body is able to produce its own vitamin D3 when your skin is exposed to the sun's ultraviolet rays, specifically ultraviolet (UVB) radiation. When UVB rays hit your skin, a chemical reaction happens: our body begins the process of converting a prohormone in the skin into vitamin D.

Hari said: (Jan 6, 2020)  
Thank you for the useful information.

Jadhavshivani said: (Aug 14, 2020)  
Morning exposure of sunlight is good for our skin which activates vitamin D present in our body and there will be less exposure of UV rays so it doesn't harm to our skin. During day time it means from 11 to 3 excess of UV rays are exposed and they are harmful to our body. And its compulsion to have every vitamin that human need, and yes its the process of one of those vitamins to gain so.

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