# physics £££

posted by .

according to einstein's mass energy relation
M= m'/root[1-(v^2/c^2)]
Where M is mass of particle when it moves with velocity 'v'
And m' is its initial mass.
When particle moves with velocity of light i.e. When 'v=c' then
M= m'/0 =infinity i.e. Infinite mass
But a photon of light can have velocity of light.
So does this possess infinite mass?!!

• physics £££ -

no, it has zero rest mass m' so its mass is undefined at any speed.
As you know of course it does have finite energy and momentum.

• physics £££ -

see Wikipedia:
" .... In empty space, the photon moves at c (the speed of light) and its energy and momentum are related by E = pc, where p is the magnitude of the momentum vector p. This derives from the following relativistic relation, with m = 0:[15]

E^{2}=p^{2} c^{2} + m^{2} c^{4}.

The energy and momentum of a photon depend only on its frequency (ν) or inversely, its wavelength (λ):

E=\hbar\omega=h\nu=\frac{hc}{\lambda}

\boldsymbol{p}=\hbar\boldsymbol{k},

where k is the wave vector (where the wave number k = |k| = 2π/λ), ω = 2πν is the angular frequency, and ħ = h/2π is the reduced Planck constant.[16]

Since p points in the direction of the photon's propagation, the magnitude of the momentum is

p=\hbar k=\frac{h\nu}{c}=\frac{h}{\lambda}. ......"

## Similar Questions

1. ### math

In the theory of relativity, the mass of a particle with velocity v is m=mo/(square root ((1- v^ 2)/ c^2)) where mo is the mass of the particle at rest and ci s the speed of light. What happens as v goes to c?
2. ### Physics

A particle with m = 3.3E-27 kg is moving with a velocity of 6.0E7m/s. It then collides with a stationary particle of mass 2m, the lighter particle then moves at a right angle to the original direction with a velocity of 2.0E7m/s. What …
3. ### physics

A proton (mass=1.67*10^-27 kg) moves with a velocity of 6.00*10^6 m/sec. Upon colliding with a stationary particle of unknown mass, the proton rebounds upon its own path with a velocity of 4.00*10^6 m/sec. The collision sends the unknown …
4. ### physics

A proton (mass=1.67*10^-27 kg) moves with a velocity of 6.00*10^6 m/sec. Upon colliding with a stationary particle of unknown mass, the proton rebounds upon its own path with a velocity of 4.00*10^6 m/sec. The collision sends the unknown …
5. ### Physics

A particle of mass M moves through the lab at 0.6c. Suddenly it explodes into two fragments. First fragment, with mass 2M/3 , moves at 0.8c in the same direction that the original particle had been moving. Determine the velocity (magnitude …
6. ### physics

A particle of mass m and initial velocity v collides elastically with a particle of mass M coming from opposite direction.After collision m has velocity V/2 at right angles to incident direction and M moves at an angle of 45 degree …
7. ### physics emergerncyy!

A particle of mass m1 = 2.5 kg moving along the x axis collides with a particle of mass m2 = 4.7 kg initially at rest. The incoming particle is deflected in the direction 24 degrees above the x axis, whereas the target particle moves …
8. ### Physics

Question: particle J with zero initial mass and X energy accelerates from a static start to 'C' (light speed) in a time frame of N and mass increases 10 to the 28th power per nanosecond- -What is the mass on particle J?
9. ### Physics

A particle of mass =6.50 kg moves with a velocity v1=x1i+y1j+z1k. A second particle of mass =3.50 kg moves with a velocity v2=x2i+y2j+z2k. And a third particle of mass =6.30 kg moves with a velocity v3=x3i+y3j+z3k. Here, (x1,y1,z1)=(-2.5,5.4,1.2), …
10. ### physics

a particle covers 1/2 distance between A and B with a velocity V0. during 1/2 of the time required to cover the remaining distance the particle moves with a velocity V1 and rest moves with a velocity V2. find the average velocity of …

More Similar Questions