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11. A bar magnet of magnetic moment M, and pole strength m is cut into two parts of equal length. The magnetic moment and pole strength of either part is

     a. M/2, m/2         b. M, m/2      c. M/2, m      d. M,m

 

12. The SI unit of Inductance, Henry can be written as

     a. Weber/Ampere  b. Volt Second/Ampere        c. Joule/Ampere²       d. Ohm Second

 

13. Let [e] denote the dimensional formula of the permittivity of the vacuum and [m] that of the permeability of vacuum. If M= mass, L= length, T= time

       and I= current, then

       a.[e]= M^-1L^-3T²I  b [e]= M^-1L^-3T⁴I²               c [m]=MLT^-2I          d ML²T^-1I

 

14. In YDSE, the two slits are illuminated with two independent identical sources of light. What happens to the interference pattern?

       a. No interference pattern is produced   b. The intensity of the bright fringes gets doubled    c. The intensity of the bright fringes becomes four times

       d. Two sets of interference patterns are produced

 

15. What happens if monochromatic light  used in YDSE , is replaced by white light

      a. The bright fringes become white        b. The central fringe is white and all other are coloured       c. All fringes are coloured      d. No fringes are           

      observed.

 

16. A Parallelmonochromatic beam of light is incident normally on a normal slit. A diffraction pattern is formed on a screen placed  perpendicular to the

       direction of the incident beam. AT the first minimum of the diffraction pattern, the phase difference between the rays coming from the two edges of the

       slit is

       a. 0         b. P/2           c. P             d. 2P

 

17. The resolution limit of the eye is 1 minute. At a distance x km from the eye, two persons stand with a lateral separation of 3m. For the two persons to

      be just resolved by the naked eye, x should be

      a. 10km    b. 15km        c. 20km         d. 30km

 

18. A star is moving away from the earth with a velocity 10⁵ m/s. The shift in the spectral line of 5700Å as observed on earth is

       a. 0.53 Å           b. 1.06 Å       c. 1.90 Å       d. 3.80 Å

 

19. The frequency of  a radar is 780 MHz. The frequency of the reflected wave from an aeroplane is increased by 2.6 KHz. The velocity of the aeroplane

       is

       a. 0.25 km/s       b. 0.5 km/s     c.1.0 km/s      d. 2.0 km/s

 

20. A concave mirror of focal length f, produces a magnification m. The focal length of the mirror is

       a. (m-1)f/m        b. (m+1)f/m             c. (m-1)f        d. (m+1)f