JEE MAINS PHYSICS-solved examples-2 march-14

• In the first problem, one can simply conserve the momentum in two directions to reach on the answer. Note that had the collision been head on then there could have been 100% transfer of the energy.
• In the second problem only notable point is that don't use the relation E= hc/ l for electron or any matter to find the wavelength associated with it.
• In third problem the concept here used that beat frequency is the inverse of the time interval of the intensity function.
  
  Good Luck