31. For pair production, hf:

A. Should be greater than moc2
       
B. Should be greater than 1/2	m c
      
C. Should be greater than 2moc2
      
D. Should be less than	 1/2m c
 

32. When a ball is thrown upwards, then its de-Broglie’s wavelength will be
minimum?.

A. At the point of projection
       
B. At maximum height
       
C. At the point midway between the initial and final points
       
D. Both A and B
 

33. If an electron, neutron and a proton have the same de- Broglie wavelength then which particle will have the greatest speed:

A. Electron
       
B. Alpha particle
       
C. Neutron
       
D. Proton
 
 

34. Uncertainty principle is due to.

A. Wave nature of light
      
B. Particle nature of light
      
C. Wave-particle duality
      
D. None of these

 

35. Compton shift in wavelength depends upon:

A. Wavelength of incident photon          
B. Mass of electron
       
C. Scattering angle of photon               	
D. All of these
 

36. A pair of electron and positron are produced in pair production to conserve:

A. Mass                                                                        
B. Energy
       
C. Momentum                                                              
D. Charge
 

37. If K.E of electron is doubled in Davison Germer experiment then its de-
Broglie’s wavelength is:

A. Doubled                                                                   
B. Halved
       
C. Increased by four times                                            
D. None of these
 

38. For accurate measurement of position of electron, the wavelength of light
used should be:

A. Small                                                                      
B. Medium
       
C. Large                                                                       
D. Zero
 

39. Compton’s effect is typically given by:

A.   rays                                       
B. X-rays
       
C. Ultraviolet                                                  
D. Infrared
 

40. Dimensions of ℎ/m.c are:

A. [L]                                                                  
B. [T]  
       
C. [L-1]                                                                 
D. [T-1]