bcafamilyMordern Physics
74. A nucleus reactor has a power of 16 kW if the energy per fission is 200 MeV then number of fissions per second is [2075]
5 x 1017
5 x 1016
5 x 1015
5 x 1014
75. To obtain p-type silicon semiconductor, pure silicon may be doped with [2075]
Aluminum
Oxygen
phosphorous
copper
74. According to Bohr's model of the H-atom, the radius of stationary orbit characterized by the principle of quantum number n is proportional to [2074]
π / n
n2
n
1/n2
69. The photoelectric is based on the law of conservation of. [2073]
energy
mass
momentum
angular momentum of photons
70. When a radioactive element emits a β-particle the mass number of the atom [2073]
increase by one
decreases by one
remains the same
decreases by four
75. In which region of electromagnetic spectrum does the layman series of atom Lie?[2073]
Ultraviolet
visible
infrared
microwave
71. The ratio of specific charge of proton to that of an alpha particle is [2072]
1:4
1:2
4:1
2:1
73. The approximate radius of aluminum nucleus is [2072]
1.5 Fermi
2.5 Fermi
4.5 Fermi
13.5 Fermi
74. The kinetic energy of a particle is doubled, de Broglie wavelength becomes [2072]
2 times
4 times
2 times
1/2 times
75. Half life and mean life of a radioactive element are related. Choose correct answer from the following [2072]
Half life is less than the mean life
Half life is more than the mean life
mean life and the half life are the same
mean life is exactly two times the half life
72. The angular momentum of electron in the hydrogen atom in the ground state is [2071]
h/2π
h/4π
h2
2h
73. The approximate radius of aluminum nucleus is [2071]
1.5 Fermi
2.5 Fermi
4.5 Fermi
13.5 Fermi
74. The kinetic energy of a particle is doubled, de Broglie wavelength becomes [2071]
2 times
4 times
2 times
1/2 times
75. Half life and mean life of a radioactive element are related. Choose correct answer from the following [2071]
Half life is less than the mean life
Half life is more than the mean life
mean life and the half life are the same
mean life is exactly two times the half life
72. Electron in the atom are held due to [2071]
Nuclear forces
Coulomb forces
Van der Waals force
Gravitational forces
73. Which series of H atom lies in visible region?[2071]
Lyman
Bracket and Paschen
Balmer
Paschen
74. The half-life of a substance is 1600 years. The mean life is [2071]
1600 yrs
3200 yrs
800 yrs
2309 yrs
75. Rydberg constant is [2071]
Same for all element
Different for different element
A universal constant
Is diffrent for lighter element but same for heavier elements
69. A particle of mass 10-31 kg is moving with a speed of 105m/s. The De-Broglie wavelength of the particle is ...... [2070]
6.63 x 10-8 m
6.63 Å
66.3 Å
6.63 x 10-7m
71. Hard X-rays are compared to soft X-rays have[2070]
Higher Intensity
Lower frequency
Higher Frequency
Higher Speed
72. The mass of α-particle is [2070]
Equal to the mass of four protons
Equal to the mass of four neutrons
Equal to the masses of 2 protons and 2 neutrons
Less than the sum of masses of 2 protons and 2 neutrons
