# Practice Quiz (Viva Questions)

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Viva Questions Determine the wavelength of the laser light by diffraction grating and demonstration.

1. What is Interference?

2. What is full form of the LASER?

3. What is the condition for constructive interference?

4. Does diffracted Waves can interfere?

5. What is grating Element?

6. What is spontaneous and stimulated emission process?

7. What is diffraction grating?

8. What are the Laser light characteristics ?

9. What is population Inversion?

10. What is the standard value of Red Color wavelength in He-Ne gas LASER?

11. Why do you use n lembda= d sin theta formula? What is the origin to derive this formula for this experiment?

12. How to find the grating element of a given diffraction grating having 1500 Lines Per Inch (LPI)?

13. What is diffraction?

14. What is the formula for to find the percentage error?

Observed value=A

Standard value=B

1. $Error&space;=&space;\frac{A-B}{B}\times&space;100$
2. $Error&space;=&space;\frac{A-B}{A}\times&space;100$
3. $Error&space;=&space;\frac{A-B}{2B}\times&space;100$
4. $Error&space;=&space;\frac{2A-B}{B}\times&space;100$