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
विकल्प
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
Calculate the radius of second Bohr orbit in hydrogen atom from the given data.
Mass of electron = 9.1 x 10-31kg
Charge on the electron = 1.6 x 10-19 C
Planck’s constant = 6.63 x 10-34 J-s.
Permittivity of free space = 8.85 x 10-12 C2/Nm2
Using Bohr's postulates of the atomic model, derive the expression for radius of nth electron orbit. Hence obtain the expression for Bohr's radius.
Calculate the radius of Bohr’s fifth orbit for hydrogen atom
Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the orbit.
If the photon of the wavelength 150 pm strikes an atom and one of its inner bound electrons is ejected out with a velocity of 1.5 × 107 ms–1, calculate the energy with which it is bound to the nucleus.
If the velocity of the electron in Bohr’s first orbit is 2.19 × 106 ms-1, calculate the de Broglie wavelength associated with it.
State Bohr postulate of hydrogen atom that gives the relationship for the frequency of emitted photon in a transition.
Using Bohr’s postulates, obtain the expression for total energy of the electron in the nth orbit of hydrogen atom.
Using Bohr’s postulates for hydrogen atom, show that the total energy (E) of the electron in the stationary states tan be expressed as the sum of kinetic energy (K) and potential energy (U), where K = −2U. Hence deduce the expression for the total energy in the nth energy level of hydrogen atom.
When a photon stimulates the emission of another photon, the two photons have
(a) same energy
(b) same direction
(c) same phase
(d) same wavelength
Evaluate Rydberg constant by putting the values of the fundamental constants in its expression.
Which of these statements correctly describe the atomic model according to classical electromagnetic theory?
In Bohr model of hydrogen atom, which of the following is quantised?
According to Bohr's model of hydrogen atom, an electron can revolve round a proton indefinitely, if its path is ______.
Calculate the energy and frequency of the radiation emitted when an electron jumps from n = 3 to n = 2 in a hydrogen atom.
For the ground state, the electron in the H-atom has an angular momentum = h, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true ______.
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.
The wavelength in Å of the photon that is emitted when an electron in Bohr orbit with n = 2 returns to orbit with n = 1 in H atom is ______ Å. The ionisation potential of the ground state of the H-atom is 2.17 × 10−11 erg.
The total energy of an electron in the nth orbit of the hydrogen atom is proportional to ______.
Write the ionisation energy value for the hydrogen atom.
