Multiple Choice QuestionsThe symbolic representation of four logic gates
The logic symbols for OR, NOT and NAND gates are respectively
(iii), (iv), (ii)
(iv), (i), (iii)
(iv), (ii), (i)
(iv), (ii), (i)
A transistor is operated in common-emitter configuration at Vc = 2 volts such that a change in the base current from 100 μ A to 200 μ A produces a change in the collector current from 5 mA to 10 mA. The current gain is
75
100
150
150
In a Rutherford scattering experiment when a projectile of charge Z1 and mass M1 approaches a target nucleus of charge Z2 and mass M2, the distance of closest approach is ro.The energy of the projectile is
directly proportional to M1 x M2
directly proportional to Z1Z2
inversely proportional to Z1
inversely proportional to Z1
B.
directly proportional to Z1Z2
The particle of mass M1 and charge z1 possess initial velocity u when it at a large distance from the nucleus of an atom having atomic number z2. At the distance of closest approach, the kinetic energy of the particle is completely converted to potential energy. Mathematically,
so the energy of the particle is directly proportional to z1z2
The ionisation energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between
n = 3 to n =2 states
n = 3 to n = 1 states
n = 2 to n = 1 states
n = 2 to n = 1 states
The mean free path of electrons in a metal is 4 x 10-8 m. The electric field which can give on an average 2 eV energy to an electron in the metal will be in unit of V m-1
8 x 107
5 x 10-11
8 x 10-11
8 x 10-11
The number of photoelectrons emitted from light of a frequency v (higher than the threshold frequency vo) is proportional to
v-vo
threshold frequency (vo)
the intensity of light
the intensity of light
Monochromatic light of wavelength 667 nm is produced by a helium-neon laser. The power emitted is 9 mW. The number of photons arriving per second on the average at a target irradiated by this beam is
9 x 1017
3 x 1016
9 x 1015
9 x 1015
The figure shows a plot of photocurrent versus anode potential for a photosensitive surface for three different radiations. Which one of the following is a correct statement?
Curves a and b represent incident radiations of different frequencies and different intesities
Curves a and b represent incident radiations of same frequency but of different intesities
Curves b and c represent incident radiations of different frequencies and different intensities
Curves b and c represent incident radiations of different frequencies and different intensities
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