MCQ ON LASER

Q1. The emission process responsible for producing laser is

a)Spontaneous emission b) stimulation emission   c.) ultraviolet emission  d.) infrared emission

Q2. For laser action to occur, the medium must have at least

a.) Four energy levels b.) two energy levels c.) three energy levels d.) none of above

Q3. Ordinary light does not have

a.) monochromaticity b.) coherence c.) high intensity d.) all of above

Q4. The life time of metastable state is

a.)10^-5 sec b.) 10^-3 sec c.)10^-8 sec d.)  10^-7 sec

Q5. The ratio of Einstein’s coefficients A and B is

a) 8πh v³/c³                   b.) 2π h³v³/c³                c.) (2π hv/c)³               d.) 8 hc/π

Q6. In ruby laser which ions give rise to laser action?

a.) Al₂O₃              b.)Al³⁺                   c.)  Cr³⁺            d.)  none of them

Q7. Which of the following laser have the highest efficiency?

a.)Ruby        b.)  semiconductor          c.) He-Ne      d.) carbon-dioxide

Q8. The wave length of emitted light in Ruby laser is

a.)632.8 nm             b.)  694.3 nm                  c. 683.2 nm               d  649.3 nm

Q9. In He – Ne laser the most favorable ratio of He to Ne for satisfactory laser action is

a.) 1: 10             b.)   10 : 11                    c.)   10: 1                 d.)   11:10

Q10. CO₂ laser produces laser light in the range of wavelength

a.) 50μm –  24.8μm          b.)  20μm – 10.6μm       c.)  24.8μm –  20μm        d.)  10.6μm –  9.4μm

Q11. The wavelength of light emitted from He-Ne laser is

a.) 6843 A⁰              b.)  6328 A⁰            c.)  6943 A⁰                d.) 6523 A⁰ 

Q12. Pulsed laser light is produced from

a ) ruby laser      b.) carbon laser             c.) CO₂ laser            d.) none of above

Q13.Usually, population inversion in gas laser is achieved by

a.) optical pumping   b) electric discharge      c.) thermal pumping      d.) chemical pumping

Q14. Which of the following is not a characteristic of LASER?

a.) coherence  b) .high divergence            c.) highly directional            d.) extreme brightness

Q15. The hologram contains the information about,

a.) amplitude of the object      b.) phase of the object     c) both (a) & (b)         d.) none of the above

Q16. The information carrying capacity of the hologram is,

a.) less than ordinary photograph                       b.) more than ordinary photograph

c.) equal to ordinary photograph                          d.) none of the above

Q17. In normal state of energy the incident high energy photons will be

a.) stimulated   b.) absorbed          c.) cause X-ray emission       d.) cause laser production

Q18. In He-Ne laser the lasing action is produced by

a.) He-Ne both   b.) Ne only          c.) Electrons of He            d.) none of above

Q19. The velocity of laser light is,

a.) Less than ordinary              b.) light more than ordinary light

c.) equal to ordinary light       d.) Different for different colours

Q20.  Some lasers are referred to as being “cw.” What does “cw” mean?

a.) Circular wave         b.) constant white            c.) continuous wave            d. clear white

Q21. In CO₂ laser the discharge tube contains a mixture of CO₂, N₂ and He in the ratio of

a.) 15% : 70% : 15%   b.) 70% : 15% : 15%    c.) 15% : 15% : 70%     d.) 25% : 25%:50%

Q22. What was the active medium used in the first working laser ever constructed?

1. A diamond block             b.) He-Ne  gas         c.) ruby rod                d.)  CO₂ gas

Q23. In Ruby LASER , the host crystal is

a.)     Al₂O₃               b.)      MnO₂                        c.)    CaCO₃                       d.)  none of above

Q24. In spontaneous emission process the photon is

a.Lost                  b.) created                           c.  (a) & (b) both              d. none of the above

Q25. In stimulated emission process the number of coherent photons are;

a.) 3                    b.)1                       c) 2                    d. none of the above

READ ALSO:

Semiconductor diode LASER

Ruby Laser Construction and Working

Semiconductor LASER Construction and Working

Six Major Misconceptions in LASER what Student Thinks

How to Find LASER Wavelength Using a Diffraction Grating in the Lab

He-Ne gas Laser: Its Principle, Construction and Working

Carbon dioxide (CO2) gas Laser

Answer Keys LASER MCQ:

These are answers of MASER MCQ.

1Correct : b

2Correct : c

3Correct : d

4Correct : b

5Correct : a

6Correct : c

7Correct : b

8Correct : b

9Correct : c

10Correct : d

11Correct : b

12Correct : a

13Correct : b

14Correct : b

15Correct : c

16Correct : b

17Correct : b

18Correct : b

19Correct : c

20Correct : c

21Correct : c

22Correct : c

23Correct : a

24Correct : c

25Correct : c