61.

A ray of light passes through an equilateral prism such that an angle of incidence is equal to the angle of emergence and the latter is equal to  the angle of prism. The angle of deviation is

• 45°

• 39°

• 20°

• 30°

The dispersive power of the material of lens of focal length 20 cm is 0.08. The longitudinal chromatic aberration of the lens is

• 0.08 cm

• 0.08/20 cm

• 1.6 cm

• 0.16 cm

A single slit is located effectively at infinity in front of a lens of focal length 1 m and it is illuminated normally with light of wavelength 600 nm. The first minima on either side of central maximum are separated by 4 mm. Width of the slit is

• 0.1 mm

• 0.2 mm

• 0.3 mm

• 0.4  mm

The wavelength of a 1 keV photon is 1.24 nm. The frequency of 1 MeV photon is

• 1.24 × 10¹⁵ Hz

• 2.4 × 10²⁰ Hz

• 1.24 × 10¹⁸ Hz

• 2.4 × 10²⁴ Hz

A photon of energy 8 eV is incident on metal surface of threshold frequency 1.6 x 10¹⁵ Hz. The kinetic energy of the photoelectrons emitted (in eV) : (Take h = 6 x 10^-34 J-s)

• 1.6

• 6

• 2

• 1.2

C¹⁴ has half-life 5700 year. At the end of 11400 years, the actual amount left is

• 0.5 of original amount

• 0.25 of original amount

• 0.125 of original amount

• 0.0625 of original amount

The ionization potential of hydrogen is 13.6 V. The energy required to remove an electron from the second orbit of hydrogen is

• 3.4 eV

• 6.8 eV

• 13.6 eV

• 1.51 eV

As the electron in Bohr orbit of hydrogen atom passes from state n = 2 to n= 1, the kinetic energy K and potential energy U change as

• K two-fold, U four-fold

• K four-fold, U two-fold

• K four-fold, U also four-fold

• K two-fold, U also two-fold

The depletion layer of a p-n junction

• is of constant width irrespective of the bias

• acts like an insulating zone under reverse bias

• has a width that increases with an increase in forward bias

• is depleted of ions

For the given circuit shown below, to act as full wave rectifier, the AC input should be connected across ....and .... and the DC output would appear across ...... and.....

• B and D and A and C

• B and A and C and D

• C and A and B and D

• C and D and B and A