10 important MCQs of laser, ruby laser and helium neon laser

I. What is the pumping source in Ruby laser?

  1. Electrical Pumping
  2. Optical
  3. Chemical
  4. None of the above

II. What is the output in wavelength of ruby laser?

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Should one take acidic liquid items in copper bottle: My experience

Hello friends,

Today I want to share my personal bad experience with you. You must have heard that copper is good for health and many of us drink water in copper bottle or glass. Many of us drink water in copper bottle or glass by storing water through out night and then drink water in morning in empty stomach.

I have suffered from fever few days back and also stomach was upset. One day before going for office in morning, I thought of mixing oral rehydration salts (ORS) available commonly in market chemist shop. The ORS is used to replace lost fluid in body. It has sodium, potassium glucose etc. So it is very good in case of dehydration.

Thus I have mixed ORS with water placed in copper bottle. Then I went for office and drank water regularly. At about 3 pm, I again drank water placed in copper bottle but it was quite bitter at that time. Therefore I left it. But after some time I have constant bitter taste in my mouth. When I reached home, I was feeling nausea and stomach pain. Then by chance I saw the color of water. To my surprise, the color of water was blue.

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How to save water by doing small things

Dear Friends, Our earth is going through a very vital phase. We are facing shortage of water due to water crisis in many parts of world. But there are many persons among us who waste water like any thing. They do not want to listen to any one. It is our responsibility to tell them that water is necessity and we have to save water for us and for others. There may be many methods to save water, to recycle it.

I want to share one of the methods that I have adopted personally to recycle water. Most of us have flower pots in our house where we take care of our plants like our kids. We give them food, water, sun light so that they can grow.

water is life

We also have ROs filters that is reverse osmosis filters installed in our homes also. When we fill water in the tank of ROs then we must have seen that water gets filtered and water also comes through the side pipe. It was getting wasted. This water was going into sink and getting waste. One day I thought to use this water and placed an empty jug under it. When the jug got filled with water, I have used this water to water the plants in flower pots. This way I have reused the water getting waste and did my little bit to save water.

Dear Friends, You may also suggest little bit methods to save water or reuse or recycle water for our Dearest Earth. Please drop your suggestions in comment boox.

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How Electronic Devices Affect Sleep Quality

Sleep. You remember that? It was that lovely revitalising thing we all used to do every night. Pfft! Not any longer.

It seems these days everyone I speak to, from family members to friends, is suffering from some sleeping disorder or another. If it isn’t problems falling to sleep, it’s frequent waking and in some cases full blown insomnia. Eek! Continue reading “How Electronic Devices Affect Sleep Quality”

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WinnerScience Innovative Idea Contest -2015 (WIIC-2015)

Dear friends,

Today we proudly announce the First WinnerScience Innovative Idea Contest- 2015 (WIIC-2015).


The objective of the WIIC is to encourage the students to solve the daily life problems with easy and innovative methods. The aim of the contest is to get the idea from your side, the idea may be in the idea form only or it may be in the practical form also. The proposal should focus on to solve the problems and it may be related to any field of science. Continue reading “WinnerScience Innovative Idea Contest -2015 (WIIC-2015)”

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Cathode rays and their 15 properties

Definition of cathode rays:

Cathode rays are the group of fast moving negatively charged particles. These negatively charged particles are electrons. These rays are shot out at a high speed from the cathode of a discharge tube at a pressure below 0.01 mm of mercury.

15 Properties of Cathode rays:

1.       Cathode rays travel in straight lines.

2.       These rays are deflected by electric field. This is obvious because these rays are nothing but electrons.

3.       These rays travel normally from the surface of cathode. Continue reading “Cathode rays and their 15 properties”

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Why laser is needed in holography

As recording process in holography is based on the principle of interference. For recording and for sustained interference, the path difference between various interfering light waves should always be less than longitudinal coherence length. For ordinary light source like mercury the coherence length is very small (≈3cm). The path difference introduced between light waves reflected from different points of object can be much more than this value. Thus interference pattern cannot be recorded. While coherence length for laser source can be as high as 600 km. As a result, sustained interference pattern will be recorded on hologram. Thus hologram cannot be made without laser source. Continue reading “Why laser is needed in holography”

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Reflection and transmission hologram

Reflection hologram: If recording material in hologram is placed such that reference beam and object beam approach it from two opposite sides, then hologram formed is called Reflection Type hologram. The interference fringes are usually parallel to the surfaces of recording medium. When such a hologram reconstructed, then reference beam and object beam lie on the same side of hologram. Continue reading “Reflection and transmission hologram”

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Transverse electric waves


In the case, the component of electric field vector E lies in the plane transverse to the direction of propagation that is there is no component of E along the direction of propagation where as a component of magnetic field vector H lies along the direction of propagation.

Derivation of transverse electric waves in parallel planes:

As the direction of propagation is assumed as z-direction, therefore

Ez = 0 and Hz is not equal to 0

Now by substituting Ez = 0 in equation (8) of article “waves between parallel planes”, we get

Ex= 0 and Hy = 0 and

Ey not equals to 0 , H not equals to 0

Now write wave equations for free space in terms of E

Ñ2E =g2gE

= -w2μεE                     (because g2g = (jwμ) (σ + jwε) As σ =0(from                                                                            assumption  (c) of article “waves between parallel planes” => g2g =-w2με)

Or                    d2E/dx2 + d2E/dy2 + d2E/dz2 = -w2μεE

For the y component, the wave equation will become Continue reading “Transverse electric waves”

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