Home
Class 12
PHYSICS
Consider 3rd orbit of He^+ (Helium), usi...

Consider 3rd orbit of `He^+` (Helium), using non-relativistic approach , the speed of electron in this orbit will be [given `k=9xx10^(9)` constant, Z=2 and h(Planck's constant) =6.6`xx10^(-34)J*s`]

A

`2.92xx10^6 m//s`

B

`1.46xx10^6 m//s`

C

`0.73xx10^6m//s`

D

`3.0xx10^8m//s`

Text Solution

Verified by Experts

The correct Answer is:
B
According to Bohr's quantum condition,
`mv_nr_n=n(h)/(2pi) or, v_n=(hn)/(2pimr_n)`
`"Again",r_n prop (n^2)/(mZ) or,mr_n prop(n^2)/Z,`
`"Hence" ,v_n prop n(Z)/(n^2) i.e., v_n prop Z/n`
For ground state of hydrogen , Z=1 and n=1,
`therefore v=c/(137)`
`therefore "For third orbit of "He^+(Z=2)`,
`v=c/(137)*2/3=(3xx10^(8))/(137)xx2/3=1.46xx10^6 m//s`
Promotional Banner

Topper's Solved these Questions

  • ATOM

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE WITH SOLUTIONS (NEET)|3 Videos

  • ATOM

    CHHAYA PUBLICATION|Exercise CBSE SCANNER|18 Videos

  • ATOM

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE WITH SOLUTIONS (JEE Main)|7 Videos

  • ALTERNATING CURRENT

    CHHAYA PUBLICATION|Exercise CBSE SCANNER|33 Videos

  • ATOMIC NUCLEUS

    CHHAYA PUBLICATION|Exercise CBSE SCANNER|14 Videos

Similar Questions

Explore conceptually related problems

The de Broglie wavelength of an electron (mass =1 xx 10^(-30)kg , charge =1.6 xx 10^(-19)C ) with a kinetic energy of 200eV is (Planck's constant =6.6 xx 10^(-34)Js )

Under what potential difference should an electron be accelerated to obtain electron waves of lamda = 0.6 Å ? Given, mass of electron, m = 9.1 xx 10^(-31) kg , Planck's constant, h = 6.62 xx 10^(-34) J.s

Work functions for zinc is 3.6 eV. If threshold frequency for zinc is 9 xx 10^(14) cps, determine the value of Planck's constant. ( 1eV = 1.6 xx 10^(-12) erg)

An electron is revolving in the third orbit of a hydrogen atom. What is its angular momentum? [h = 6.6 xx 10^-34 JS]

At what temperature would the kinetic energy of a gas molecule be equal to the energy of photon of wavelength 6000Å ? Given, Boltzmann's constant, k = 1.38 xx 10^(-23) J .K^(-1) , Planck's constant, h = 6.625 xx 10^(-34) J.s

The kinetic energy of sub-atomic particle is 5.85 xx 10^(-25) J. Calculate the frequency of the particle wave. (Planck’s constant, h = 6.626 xx 10^(-34) Js)

Determine the de Broglie wavelength of an electron moving with velocity 10^(6) m.s^(-1) . What will be the de Broglie wavelength of a proton, moving with the same velocity? Given, Planck's constant = 6.62xx10^(-34) J.s , mass of electron = 9.1xx10^(-31) kg , mass of proton is 1840 times that of an electron.

A metal has a work function of 2eV. It is illuminated by monochromatic light of wavelength 500 nm, calculate (i) the threshold wavelength, (ii) the maximum energy of photoelectrons, (iii) The stopping potential. Given Planck's constant h = 6.6 xx 10^(-34)J.s , charge on electron e = 1.6 xx 10^(-19) C and 1eV = 1.6 xx 10^(-19)J

Calculate the velocity of an electron having de Broglie wavelength of 200 Å. [m=9.11xx10^(-31)kg,h=6.626xx10^(-34)J*s] .

The ionization energy of hydrogen atom in the ground state is 1312 kJ "mol"^(-1) . Calculate the wavelength of radiation emitted when the electron in hydrogen atom makes a transition from n = 2 state to n = 1 state (Planck’s constant, h = 6.626 xx 10^(-34) Js , velocity of light, c = 3 xx 10^8 m s^(-1) , Avogadro’s constant, N_A = 6.0237 xx 10^23 "mol"^(-1) ).