Interference and Diffraction Multiple Choice Questions and Answers

1. Colors in thin films are because of

1. Dispersion
2. Compton effect
3. Interference
4. Diffraction

2. Diffraction due to circular aperture If a light passes through a small pinhole, and incident on a screen. What will be observed on the screen?

1. A sharp bright point of the width equal to width the pinhole
2. A bright point of the width equal to width the pinhole but of less intensity
3. A bright ring at the centre surrounded by alternate dark and bright rings
4. A diffused bright point

3. Diffraction is special type of

1. Reflection
2. Refraction
3. Interference
4. Polarization

4. Extended source is needed in

1. Youngs double slit experiment
2. Bi prism Experiment
3. Newtons Ring Experiment
4. None of them

5. Find the maximum value of resolving power of a grating 3 cm wide having 5000 lines per cm, if the wavelength of light used is 5890 A^o.

1. 40000
2. 45000
3. 4500
4. 5000

6. For all transparent material substances, the index of refraction

1. is less than 1
2. is greater than 1
3. is equal to 1
4. Could be any of the given answers; it all depends on optical density

7. Fraunhofer diffraction at a Plane Grating. What is the meaning of grating element for a diffraction grating?A It is the width of a single slit

1. It is the width of the opaque space
2. It is the distance between two slits
3. It is the width of diffraction grating

8. Fraunhofer diffraction is observed when

1. Only screen is placed at finite distance
2. source is placed at finite distance
3. neither source nor screen is at finite distance
4. None of these

9. Fresnels type diffraction is observed when

1. Only screen is placed at finite distance
2. Only source is placed at finite distance
3. Both source and screen are at finite distance
4. Neither source nor screen is at finite distance

10. Fringe spacing is defined as the distance between two Consecutive

1. Crests
2. Bright fringes only
3. Dark fringes only
4. Bright or dark fringes