# Atoms and Nuclei · Physics · MHT CET

Start Practice## MCQ (Single Correct Answer)

MHT CET 2023 14th May Evening Shift

Ratio of longest wavelength corresponding to Lyman and Balmer series in hydrogen spectrum is

MHT CET 2023 14th May Evening Shift

Half life of radio-active element is 1600 years. The fraction of sample remains undecayed after 6400 years will be

MHT CET 2023 14th May Morning Shift

Frequency of the series limit of Balmer series of hydrogen atom in terms of Rydberg's constant (R) and velocity of light (c) is

MHT CET 2023 14th May Morning Shift

If the radius of the first Bohr orbit is '$$r$$' then the de-Broglie wavelength of the electron in the $$4^{\text {th }}$$ orbit will be

MHT CET 2023 14th May Morning Shift

Magnetic field at the centre of the hydrogen atom due to motion of electron in $$\mathrm{n}^{\text {th }}$$ orbit is proportional to

MHT CET 2023 13th May Evening Shift

An excited hydrogen atom emits a photon of wavelength $$\lambda$$ in returning to ground state. The quantum number $$n$$ of the excited state is ($$R=...

MHT CET 2023 13th May Evening Shift

When an electron is excited from its 4 th orbit to 5 th stationary orbit, the change in the angular momentum of electron is approximately.
(Planck's c...

MHT CET 2023 13th May Morning Shift

A radioactive sample has half-life of 5 years. The percentage of fraction decayed in 10 years will be

MHT CET 2023 13th May Morning Shift

An isotope of the original nucleus can be formed in a radioactive decay, with the emission of following particles.

MHT CET 2023 12th May Evening Shift

Two different radioactive elements with half lives '$$\mathrm{T}_1$$' and '$$\mathrm{T}_2$$' have undecayed atoms '$$\mathrm{N}_1$$' and '$$\mathrm{N}...

MHT CET 2023 12th May Evening Shift

In Balmer series, wavelength of the $$2^{\text {nd }}$$ line is '$$\lambda_1$$' and for Paschen series, wavelength of the $$1^{\text {st }}$$ line is ...

MHT CET 2023 12th May Morning Shift

In Lyman series, series limit of wavelength is $$\lambda_1$$. The wavelength of first line of Lyman series is $$\lambda_2$$ and in Balmer series, the ...

MHT CET 2023 12th May Morning Shift

The wavelength of radiation emitted is '$$\lambda_0$$' when an electron jumps from the second excited state to the first excited state of hydrogen ato...

MHT CET 2023 11th May Evening Shift

According to Bohr's theory of hydrogen atom, the total energy of the electron in the $$\mathrm{n}^{\text {th }}$$ stationary orbit is

MHT CET 2023 11th May Evening Shift

Bohr model is applied to a particle of mass '$$\mathrm{m}$$' and charge '$$\mathrm{q}$$' moving in a plane under the influence of a transverse magneti...

MHT CET 2023 11th May Evening Shift

The orbital magnetic moment associated with orbiting electron of charge '$$e$$' is

MHT CET 2023 11th May Morning Shift

An electron in the hydrogen atom jumps from the first excited state to the ground state. What will be the percentage change in the speed of electron?...

MHT CET 2023 11th May Morning Shift

In a radioactive disintegration, the ratio of initial number of atoms to the number of atoms present at time $$t=\frac{1}{2 \lambda}$$ is [$$\lambda=$...

MHT CET 2023 10th May Evening Shift

The ratio of the velocity of the electron in the first Bohr orbit to that in the second Bohr orbit of hydrogen atom is

MHT CET 2023 10th May Morning Shift

The shortest wavelength in the Balmer series of hydrogen atom is equal to the shortest wavelength in the Brackett series of a hydrogen like atom of at...

MHT CET 2023 10th May Morning Shift

The ratio of longest to shortest wavelength emitted in Paschen series of hydrogen atom is

MHT CET 2023 9th May Evening Shift

The force acting on the electron in hydrogen atom (Bohr' theory) is related to the principle quantum number '$$n$$' as

MHT CET 2023 9th May Evening Shift

The wavelength of light for the least energetic photons emitted in the Lyman series of the hydrogen spectrum is nearly [Take $$\mathrm{hc}=1240 ~\math...

MHT CET 2023 9th May Morning Shift

The ratio of wavelengths for transition of electrons from $$2^{\text {nd }}$$ orbit to $$1^{\text {st }}$$ orbit of Helium $$\left(\mathrm{He}^{++}\ri...

MHT CET 2023 9th May Morning Shift

For an electron moving in the $$\mathrm{n}^{\text {th }}$$ Bohr orbit the deBroglie wavelength of an electron is

MHT CET 2023 9th May Morning Shift

If an electron in a hydrogen atom jumps from an orbit of level $$n=3$$ to orbit of level $$n=2$$, then the emitted radiation frequency is (where R = R...

MHT CET 2022 11th August Evening Shift

Using Bohr's model, the orbital period of electron in hydrogen atom in the $$\mathrm{n}^{\text {th }}$$ orbit is $$\left(\varepsilon_0=\right.$$ permi...

MHT CET 2022 11th August Evening Shift

The wave number of the last line of the Balmer series in hydrogen spectrum will be
(Rydberg's constant $$=10^7 \mathrm{~m}^{-1}$$ )

MHT CET 2021 24th September Evening Shift

The half life of a radioactive substance is 30 minute. The time taken between 40% decay and 85% decay of the same radioactive substance is

MHT CET 2021 24th September Evening Shift

The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest en...

MHT CET 2021 24th September Morning Shift

An electron makes a transition from an excited state to the ground state of a hydrogen like atom. Out of the following statements which one is correct...

MHT CET 2021 24th September Morning Shift

The ratio of maximum to minimum wavelength in Balmer series of hydrogen atom is

MHT CET 2021 23rd September Evening Shift

Energy of electron in the second orbit of hydrogen atom is $$\mathrm{E}$$. The energy of electron '$$\mathrm{E}_3$$' in the third orbit of helium $$(\...

MHT CET 2021 23th September Morning Shift

The shortest wavelength for Lyman series is 912 $$\mathop A\limits^o $$. The longest wavelength in Paschen series is

MHT CET 2021 23th September Morning Shift

In the Bohr model, an electron moves in a circular orbit around the nucleus. Considering an orbiting electron to be a circular current loop, the magne...

MHT CET 2021 23th September Morning Shift

The energy of an electron in the excited hydrogen atom is $$-3.4 \mathrm{~eV}$$. Then according to Bohr's theory, the angular momentum of the electron...

MHT CET 2021 22th September Evening Shift

In $$n^{\text {th }}$$ Bohr orbit, the ratio of the kinetic energy of an electron to the total energy of it, is

MHT CET 2021 22th September Evening Shift

If '$$E$$' and '$$L$$' denote the magnitude of total energy and angular momentum of revolving electron in $$\mathrm{n}^{\text {th }}$$ Bohr orbit, the...

MHT CET 2021 22th September Evening Shift

Two radioactive materials $$X_1$$ and $$X_2$$ have decay constants '$$5 \lambda$$' and '$$\lambda$$' respectively. Initially, they have the same numbe...

MHT CET 2021 22th September Morning Shift

A nucleus breaks into two nuclear parts, which have their velocity ratio $$2: 1$$. The ratio of their nuclear radii will be

MHT CET 2021 21th September Evening Shift

Ratio centripetal acceleration for an electron revolving in 3rd and 5th Bohr orbit of hydrogen atom is

MHT CET 2021 21th September Morning Shift

When an electron in hydrogen atom jumps from third excited state to the ground state, the de-Broglie wavelength associated with the electron becomes...

MHT CET 2021 21th September Morning Shift

'$$\lambda_1$$' is the wavelength of series limit of Lyman series, '$$\lambda_2$$' is the wavelength of the first line line of Lyman series and '$$\la...

MHT CET 2021 20th September Evening Shift

A sample of radioactive element contains $$8 \times 10^{16}$$ active nuclei. The halt-life of the element is 15 days. The number of nuclei decayed aft...

MHT CET 2021 20th September Evening Shift

The P.E. 'U' of a moving particle of mass 'm' varies with 'x'-axis as shown in figure. The deBroglie wavelength or the particle in the regions $$0 \le...

MHT CET 2021 20th September Evening Shift

The gyromagnetic ratio of an electron in an hydrogen atom, according to Bohr model is

MHT CET 2021 20th September Morning Shift

The electron in hydrogen atom is initially in the third excited state. When it finally moves to ground state, the maximum number of spectral lines emi...

MHT CET 2021 20th September Morning Shift

If the electron in a hydrogen atom moves from ground state orbit to 5th orbit, then the potential energy of the electron

MHT CET 2020 19th October Evening Shift

The energy levels with transitions for the atom are shown. The transitions corresponding to emission of radiation of maximum and minimum wavelength ar...

MHT CET 2020 19th October Evening Shift

Using Bohr's model, the orbital period of electron in hydrogen atom in $n$th orbit is ( $\varepsilon_0=$ permittivity of free space, $h=$ Planck's con...

MHT CET 2020 16th October Evening Shift

A radioactive nucleus emits $$4 \alpha$$-particles and $$7 \beta$$-particles in succession. The ratio of number of neutrons of that of protons, is [$$...

MHT CET 2020 16th October Evening Shift

The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest en...

MHT CET 2020 16th October Morning Shift

Using Bohr's quantisation condition, what is the rotational energy in the second orbit for a diatomic molecule? ($$I=$$ moment of inertia of diatomic ...

MHT CET 2020 16th October Morning Shift

The ratio of speed of an electron in the ground state in the Bohr's first orbit of hydrogen atom to velocity of light $$(c)$$ is ( $$h=$$ Planck's con...

MHT CET 2020 16th October Morning Shift

The force acting on the electrons in hydrogen atom (Bohr's theory) is related to the principle quantum number $$n$$ as

MHT CET 2019 2nd May Morning Shift

Bohr model is applied to a particle of mass ' $m$ ' and charge ' $q$ ' is moving in a plane under the influence of a transverse magnetic field ' $B$ '...

MHT CET 2019 2nd May Morning Shift

The angle made by orbital angular momentum of electron with the direction of the orbital magnetic moment is

MHT CET 2019 2nd May Morning Shift

The wavelength of the first line in Balmer series in the hydrogen spectrum is ' $\lambda$ '. What is the wavelength of the second line in the same ser...