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# Tag Archives: surface

## black hole

“if there is an black hole then how does it so much of gravitational pull to never even let go of the light tht passes by  its surface…????”

## Weight and inertia on moon

Say True or False; An object on the Moon weights 1/6 of what it weights on the Earth. Therefore, the object has less inertia on the Moon.( Justify your answer)

Inertia depends on mass and not on weight. The weight on moon is less not because of a decrease in mass, but due to the decrease in the acceleration due to gravity on the surface of moon.

Inertia depends on mass and there is no change in mass when a body is taken to moon. Therefore the inertia of a body is same on moon as that on earth or anywhere else in the universe, even in a gravity free space.

## SURFACE TENSION

How does surface tension act? What is basic cause?
Answer: Surface tension is the property of a liquid by virtue of which its free surface behaves like a stretched elastic membrane.
When a blade is carefully kept on a liquid surface, it floats; but it sinks if it is dropped carelessly.

## A Falling drop! Watch the picture and explain it

You can see below the photograph of a drop of water falling on water surface. Can anyone explain the observation?

## Recent Research Publications in Physics

Mass of Neutrino

The absolute scale of neutrino masses is very important for understanding the evolution and the structure formation of the Universe as well as for nuclear and particle physics beyond the present standard model.

Elastic Scattering of He at the surface of liquid helium

Elastic scattering of 4He atoms when they approach the surface of 4He liquid, has been studied. The liquid surface is assumed to be uniform and the density profile is the same along and perpendicular to the surface. The incident 4He atom will interact with a large number of 4He atoms in the liquid near the surface of liquid 4He. Hence, the effective interaction of the incident particle will be due to many-body forces.

## Friction – a numerical

a force of 20 N is applied parallel to the surface of a horizontal table is just sufficient to make a block of mass 4.kg move on the table calculate the coefficient of friction between the block and the table

## Cosmic Rays

Do cosmic rays get reflected by a mirror?Just like the normal(visible spectrum) light, do cosmic rays and lasers get reflected by a polished surface or are they strong enough to penetrate through them? (Sangeetha Varma posted this question)

Answer: Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth’s atmosphere and surface. Cosmic rays were thought to be electromagnetic radiation in the past. Most primary cosmic rays entering the atmosphere from deep space are composed of subatomic particles that normally occur on Earth, such as protons, atomic nuclei, or electrons. However, a very small fraction are particles of antimatter, such as positrons or antiprotons. The precise nature of this remaining fraction is an area of active research.

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