Velocity of electron moving in first orbit of hydrogen is:
Correct answer: D. 2.19 x 10^6 m/sec
- A. 2.19 x 10^7 m/sec
- B. 2.18 x 10^7 m/sec
- C. 2.2 x 10^8 m/sec
- D. 2.19 x 10^6 m/sec
Explanation
The velocity of an electron in the first orbit of hydrogen can be calculated using the Bohr model formula: v = n × h / (2π × m × r), where: n is the principal quantum number (1 for the first orbit), h is Planck's constant (6.63 × 10-34 Js), m is the mass of the electron (9.1 × 10-31 kg), r is the radius of the orbit (0.529 × 10-10 m). Substituting these values gives a velocity of approximately 2.19 × 106 m/s. The other options are incorrect as they either exceed feasible values or are too high for the first orbit.
Last updated
About Atomic Spectra
Atoms emit or absorb light at specific wavelengths because electrons occupy quantized energy levels and change levels by absorbing or releasing photons. The topic covers emission and absorption spectra, spectral series, hydrogen’s line spectrum, energy-level transitions, and the relation between wavelength, frequency and photon energy.
Practise Atomic Spectra
356 free Atomic Spectra MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
1/λn = R [1/p2 - 1/n2] in this relation p= 1, 2, 3...... and n will be:
A gas discharge tube glows when a high voltage is applied because
A limitation of the Bohr model is that it
A non relativistic free electron has kinetic energy "K" If its wavelength doubles, its kinetic energy is:
A set of atoms in an excited state decays: