Multiple choice Questions on LASER and OPTICAL FIBER

                                      Multiple Choice Quiz                  Time duration: 15mins

  Roll no._____________                          Name____________     

  Class_____________                             Total no. of questions attempted_______

1) Spatial coherence is also termed as:

a.       transverse coherence                    b. lateral coherence     

c. both (a) & (b)                                  d. none of these.

2)      Pumping source inside CO₂ is

a. Optical Pumping                     b. Electrical Pumping                                         c. Chemical Pumping                  d. X-Rays Pumping.

3)       Step index fibre sustains only

a. single mode of propagation                              b. multimode of propagation

c. both (a)&(b)                                                      d. none of these             

4)      Addition of GeO2 in silica

a. Increase refractive of silica

b. Decrease refractive index of silica

c.       No effect

5)       The lorentz transformation equations will reduces to Galilean transformation equations when

a. velocity is very large                                              b. velocity is very low

c. reduction is velocity independent

6) Two events at different places which are simultaneous for observer at rest is

       a.    is simultaneous for moving observer

       b.    not simultaneous for moving observer

7) Acceptance angle is the

         a. Minimum angle of incidence                     b. Maximum angle of incidence

          c. It can be maximum or minimum depending on nature of material used in core

       8). Lasers are characterized by

a. large bandwidth                                         b. narrow bandwidth

9). Two twins A&B, A is at rest and B is moving with velocity ‘v’= 2.5*10⁵,    then after 5 years

a.       Age of B will be more than A

b.            Age of A will be more than B

c.           Age of A&B are same

               10)  Two light-sources are said to be coherent if

1)      they vibrate in same phase

2)      they vibrate with constant phase difference?

3)       (a) or (b)                                                     d.      (a) & (b)

                                         Multiple Choice Quiz                  Time duration: 15mins

                   Roll no._____________         Name____________     

                   Class_____________             Total no. of questions attempted_______

1) The reconstruction process in holography involves

a.       interference phenomenon          b. diffraction phenomenon          

                             c. both (a)&(b)                                d. none of these

2)      Can we obtain light amplification in absence of stimulated emission?

           (a) Yes            (b) No

3)      .Removable joints which allow easy, fast, manual coupling and decoupling of fibre are called

a. Fibre splices                        b. fibre connectors                                             c. fibre couplers 

4)      For single mode fibres, the V-parameter is always

            a.  ≤ 2.405         b.  ≥2.405       c.  ≤ 4.205        d.  ≥4.205  

5)      Does the light or photons have mass?

            a. Yes                 b. No

6)        A person, carrying an object of length 5m, is moving with velocity     2*10⁸m/sec. The length of object observed by person will be

                 a. 4m                b. 4.5m                 c. 5m                       d. 5.5m

7)      Theory of relativity is valid only when

           a. object is moving with large velocity       

            b. observer is moving with large velocity  

             c. both(a)&(b) are true                d. both (a)&(b) are false

8)      Wavelength of He:Ne laser is

            a. 6928 ^o A          b. 6428 ^o A         c. 6328 ^o A       d. 6398 ^o A

   9)   Which of the following quantity is variant under Galilean     transformations

         (a)  length interval                            (b) acceleration

          (c)  velocity                                     (d) mass

                10)  Resonant cavity in semiconductor-lasers consists of

              (a) intrinsic region                    (b) junction

              (c) Two ends of junction          (d) polished ends of junction 

9)       Pumping source preferred for gaseous lasers is

          (a) optical pumping             (b) electrical pumping

           (c) chemical pumping         (d) X-Ray pumping

10)   Minimum value of energy in eV required to excite an e^- from ground state to   higher state corresponds to

             (a) excitation potential                  (b) ionization potential

  (c) critical potential                      (d)   atomic excitation