MCQ
When is hydrogen stable?
- AWhen the electron jumps to higher energy levels.
- BWhen an electric field is introduced.
- CWhen a magnetic field is introduced.
- DWhen the electron is at its ground state.
✓
Answer
- When the electron is at its ground state.
Explanation:
The hydrogen atom is stable when the electron rests at the ground level of energy, i.e. when the principal quantum number, n = 1. '
In other words, when the electron is revolving in the first orbit around the nucleus, the hydrogen atom is stable.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Two lenses of focal lengths +100cm and +5cm are used to prepare an astronomical telescope. The minimum tube length will be : (final image is at ∞)
The value of electric permittivity of free space is:
Assertion : NAND or NOR gates are called digital building blocks.
Reason : The repeated use of NAND (or NOR) gates can produce all the basic or complicated gates.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
The periodic time of rotation of a certain star is 22 days and its radius is 7 × 108 metres. If the wavelength of light emitted by its surface be 4320 Å, the Doppler shift will be (1 day = 86400 sec)
|
(a) 0.033 Å |
(b) 0.33 Å |
(c) 3.3 Å |
(d) 33 Å |
In a laser tube, all the photons:
In which of the following the final image is erect?
Graph is plotted between maximum kinetic energy of electron with frequency of incident photon in Photo electric effect. The slope of curve will be:
Wavefront of a wave has direction with wave motion
|
(a) Parallel |
(b) Perpendicular |
(c) Opposite |
(d) At an angle of 𝜃 |
A heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio 8:1. the ratio of de-broglie wavelengths of fragments are:
The activity of a sample is 64 × 10–5 Ci. Its half-life is 3 days. The activity will become 5 × 10–6 Ci after
|
(a) 12 days |
(b) 7 days |
(c) 18 days |
(d) 21 days |