What type of light is needed to cause the photoelectric effect?
ultraviolet light
What is the smallest quantum of light called?
photons
Why is the mass of a photon zero?
But according to special relativity, light ALWAYS travels with the light speed c, and is NEVER at rest. And so it has zero REST mass. which means that though photons don’t have rest mass, they do have energy and thus they have mass. The pressure they exert is due to the particle nature of light.
Does a photon have rest mass?
According to electromagnetic theory, the rest mass of photon in free space is zero and also photon has non-zero rest mass, as well as wavelength-dependent.
What is the value of rest mass of photon?
What is the effective mass of photon?
A Photon has zero mass but since it can do work it is done in terms of kinetic energy. As it possesses kinetic energy, using Planck’s constant, speed of light and wavelength we can obtain a relation for calculating the effective mass. Hence, this is the effective mass of a photon of wavelength λ.
Why are photons affected by gravity?
We also knew that photons are affected by gravitational fields not because photons have mass, but because gravitational fields (in particular, strong gravitational fields) change the shape of space-time. As a star contracts, the gravitational field at its surface gets stronger, thus bending the light more.
Does gravity have effect on light?
Yes, light is affected by gravity, but not in its speed. General Relativity (our best guess as to how the Universe works) gives two effects of gravity on light. It can bend light (which includes effects such as gravitational lensing), and it can change the energy of light. The speed of light is still constant.
Does photon get affected by gravity?
Photons, whether they are particles or waves seem not to interact with this field at all acording to their speed, however they are still affected by gravity. gives some particles rest mass. The other particles, lacking rest mass, still have inertial mass, which is identical to gravitational mass.
Does gravity bend light on Earth?
Gravity bends light Light travels through spacetime, which can be warped and curved—so light should dip and curve in the presence of massive objects. This effect is known as gravitational lensing GLOSSARY gravitational lensingThe bending of light caused by gravity .
How much does light bend due to Earth’s gravity?
If a beam of light were to pass right over Earth surface, it would be bent by 0.0006 arc-seconds. Compared to the sun, which would bend it by 1.75 arc seconds.
Can even light escape from a black hole?
No light of any kind, including X-rays, can escape from inside the event horizon of a black hole, the region beyond which there is no return. The immense gravity of black holes also distorts space itself, so it is possible to see the influence of an invisible gravitational pull on stars and other objects.