When the atoms in a sample of hydrogen like atoms are in the fourth (n = 4) orbit, how many spectral lines will be emitted in the radiation spectrum of the sample?
4
5
6
9
Bragg's equation will have no solution, if
λ > 2d
λ < 2d
λ < d
λ = d
If h is Planck's constant, the momentum of a photon of wavelength 0.01 Å is
h × 10-2
h
h × 102
h × 1012
An electron is accelerated through a potential difference of 1000 volt. Velocity is nearly
3.8 × 107 m s-1
1.9 × 106 m s-1
1.9 × 107 m s-1
5.7 × 107 m s-1
Einstein's work on photoelectric effect gives support to
E = mc2
E = hν
hν = 1/2 mv2
E = h/λ
Acceleration of an electron in the first Bohr orbit is proportional to
Three-fourths of the active nuclei present in a radioactive sample decay in 3/4 s. The half-life of the sample is
1 s
½ s
¾ s
3/8 s
Which of the following are thermions?
protons
electrons
photons
positrons
A radiotransmitter operates at a frequency 1000 kHz and a power of 66 kW. Find the number of photons emitted per second.
1027
1028
1029
1030
In the phenomenon of electric discharge through gases at low pressure,the coloured glow in the tube appears as a result of
excitation of electrons in the atoms
collision between the atoms of the gas
collisions between the charged particles emitted from the cathode and the atoms of the gas
collision between different electrons of the atoms of the gas
