Doubts

[infinityzero]

What could be the possible answer ?
Acco to me it should be option (B). But i am not sure about it....

[CarlBrannen]

Here's another vote for (b).

If it were an infinite mass atom then it would be (a). With a finite mass, some of the energy of the photon will become kinetic energy of the energized atom. This means you need a little extra energy hence (b).

[kroner]

To get the answer exactly, you can use the relation $$E^2 = (pc)^2 + (m_0c^2)^2,$$ and the fact that the momentum of the atom after the collision is the same as the momentum of the photon, to get $$(Mc^2 + fh)^2 = (fh)^2 + ((M + \Delta)c^2)^2,$$ and then solve for f.

[WhoaNonstop]

To get the answer exactly, you can use the relation $$E^2 = (pc)^2 + (m_0c^2)^2,$$ and the fact that the momentum of the atom after the collision is the same as the momentum of the photon, to get $$(Mc^2 + fh)^2 = (fh)^2 + ((M + \Delta)c^2)^2,$$ and then solve for f.

Solving for f looks too haaaaaaaaard.

-Riley

[HappyQuark]

To get the answer exactly, you can use the relation $$E^2 = (pc)^2 + (m_0c^2)^2,$$ and the fact that the momentum of the atom after the collision is the same as the momentum of the photon, to get $$(Mc^2 + fh)^2 = (fh)^2 + ((M + \Delta)c^2)^2,$$ and then solve for f.

Solving for f looks too haaaaaaaaard.

-Riley

That's why Mathematica has the solve function. Just the other day I came across some really difficult algebra and had to have Mathematica break it down for me. How in the hell am I supposed to know how to solve x+2=4?

[infinityzero]

Thanks for the solution ..... please help me solve two more problems.........

[grae313]

Mind sharing where these problems are from?

[infinityzero]

Well these problems are from last year's entrance exam for PhD(physics) program at TIFR,india...