Question

                                                                    

1. For a light to be coherent light waves should have:

1. same color
2. different phases
3. same wavelength and phase
4. all wavelengths

 

2. Which phenomenon shows the wave nature of light?

1. reflection
2. refraction
3. diffraction
4. lenses

 

3. Bright fringes are a result of:

1. diffraction
2. constructive interference
3. destructive interference
4. stimulated emission

 

4. Which color will give a wider (bigger diffraction pattern) when passing through the same narrow single slit

1. red
2. green
3. blue
4. UV

 

5. In the double slits experiment, how would the fringe pattern changes if the slits were moved closer to one another

1. The pattern becomes smaller
2. The pattern becomes bigger
3. No change

 

 

                       

Answer 1

1) for the light to be coherent , light waves should have same wavelength and phase because coherent waves should abide this crieteria of being in phase and same wavelength.

2) wave nature of light is shown by diffraction of waves as waves only bend around the corners of obstacles and not the particles.

3)Bright fringes are the result of constructive interference where the two interfering beams have a path difference equal to integral multiples of wavelength , also the two waves must be coherent.

4) Red color will give a wider (bigger diffraction pattern) when passing through the same narrow single slit because the spacing between the fringes is directly proportional to the wavelength and the red colour has the biggest wavelength and hence bigger diffraction pattern.

5) in the double slits experiment, the fringe pattern becomes wider if the slits were moved closer to one another because fringe width is given by

= L/a ;

where a is the slit width