If E and P are energy and momentum of photon, then velocity of it will be

Question

a)EP

b)(E/P)^2

c)(E/P)^1/2

d)E/P

 

please explain answer is d)E/P

Answer 1

Analyze the units of E and P:

• E = mass*velocity² = mass*velocity*velocity
• P = mass*velocity

 

E/P = mass*velocity*velocity/mass*velocity = velocity

 

Option a gives mass²*velocity³

Option b gives velocity²

Option c gives velocity^1/2

 

Only option d has the units of velocity.