Advertisements
Advertisements
प्रश्न
Suppose, the electron in a hydrogen atom makes transition from n = 3 to n = 2 in 10−8 s. The order of the torque acting on the electron in this period, using the relation between torque and angular momentum as discussed in the chapter on rotational mechanics is
पर्याय
10−34 N m
10−24 N m
10−42 N m
10−8 N m
Advertisements
उत्तर
10−42 N-m
The angular momentum of the electron for the nth state is given by
`L_n = (nh)/(2pi)`
Angular momentum of the electron for n = 3,
n = 3 , `L_i = (3h)/(2pi)`
Angular momentum of the electron for n = 2, `L_f= (2h)/(2pi)`
The torque is the time rate of change of the angular momentum.
Torque `tau = (L_f - L_i)/t`
= `((2h//2pi)-(3h//2pi))/10^-8`
= `-(h//2pi)/((10^-8)`
= `(-10^-34)/10^-8 ..............[∴ h/(2pi) ≈ 10^-34 J -s ]`
= -10-42 N - m
The magnitude of the torque is `10^-42 N.m`
APPEARS IN
संबंधित प्रश्न
(i) State Bohr's quantization condition for defining stationary orbits. How does the de Broglie hypothesis explain the stationary orbits?
(ii) Find the relation between three wavelengths λ1, λ2 and λ3 from the energy-level diagram shown below.
What is the maximum number of emission lines when the excited electron of an H atom in n = 6 drops to the ground state?
The energy associated with the first orbit in the hydrogen atom is - 2.18 × 10-18 J atom-1. What is the energy associated with the fifth orbit?
What is the energy in joules, required to shift the electron of the hydrogen atom from the first Bohr orbit to the fifth Bohr orbit and what is the wavelength of the light emitted when the electron returns to the ground state? The ground state electron energy is –2.18 × 10–11 ergs.
The ratio of kinetic energy of an electron in Bohr’s orbit to its total energy in the same orbit is
(A) – 1
(B) 2
(C) 1/2
(D) – 0.5
In Bohr’s model of the hydrogen atom, the radius of the first orbit of an electron is r0 . Then, the radius of the third orbit is:
a) `r_0/9`
b) `r_0`
c) `3r_0`
d) `9r_0`
The electron in hydrogen atom is initially in the third excited state. What is the maximum number of spectral lines which can be emitted when it finally moves to the ground state?
The difference in the frequencies of series limit of Lyman series and Balmer series is equal to the frequency of the first line of the Lyman series. Explain.
Find the wavelength of the radiation emitted by hydrogen in the transitions (a) n = 3 to n= 2, (b) n = 5 to n = 4 and (c) n = 10 to n = 9.
A neutron having kinetic energy 12.5 eV collides with a hydrogen atom at rest. Nelgect the difference in mass between the neutron and the hydrogen atom and assume that the neutron does not leave its line of motion. Find the possible kinetic energies of the neutron after the event.
The light emitted in the transition n = 3 to n = 2 in hydrogen is called Hα light. Find the maximum work function a metal can have so that Hα light can emit photoelectrons from it.
According to Bohr, 'Angular momentum of an orbiting electron is quantized'. What is meant by this statement?
Calculate angular momentum of an electron in the third Bohr orbit of a hydrogen atom.
What is the energy in joules released when an electron moves from n = 2 to n = 1 level in a hydrogen atom?
The energy associated with the first orbit of He+ is ____________ J.
The radius of the innermost electron orbit of a hydrogen atom is 5.3 × 10–11m. The radius of the n = 3 orbit is ______.
The ground state energy of hydrogen atoms is -13.6 eV. The photon emitted during the transition of electron from n = 3 to n = 1 unknown work function. The photoelectrons are emitted from the material with a maximum kinetic energy of 9 eV. Calculate the threshold wavelength of the material used.
In Bohr's theory of hydrogen atom, the electron jumps from higher orbit n to lower orbit p. The wavelength will be minimum for the transition ______.
State three postulates of Bohr's theory of hydrogen atom.
