NEET Physics Atoms Class 12 Questions

In the first excited state of hydrogen atom, the energy of its electron is −3.4 eV. The radial distance of the electron from the hydrogen nucleus in this case is approximately: (Take 1 eV = 1.6 × 10⁻¹⁹ J, e = 1.6 × 10⁻¹⁹ C and \( \frac{1}{4\pi\varepsilon_0} = 9 \times 10^9 \text{ N m}^2/\text{C}^2 \))

De⁻Broglie wavelength of an electron orbiting in the n = 2 state of hydrogen atom is close to (Given Bohr radius = 0.052 nₘ)

A photon and an electron (mass m) have the same energy E. The ratio (λ_photon/λ_electron) of their de Broglie wavelengths is: (c is the speed of light)

Match List I with List II.

Given below are two statements: Statement I: Atoms are electrically neutral as they contain equal number of positive and negative charges. Statement II: Atoms of each element are stable and emit their characteristic spectrum. In the light of the above statements, choose the most appropriate answer from the options given below:

In hydrogen spectrum, the shortest wavelength in the Balmer series is λ. The shortest wavelength in the Bracket series is:

The radius of inner most orbit of hydrogen atom is 5.3×10⁻¹¹ m. What is the radius of third allowed orbit of hydrogen atom?

Let T₁ and T₂ be the energy of an electron in the first and second excited states of hydrogen atom, respectively. According to the Bohr’s model of an atom, the ratio T₁ : T₂ is:

An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is 1.227 × 10⁻² nₘ, the potential difference is:

An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is, (nearly) (mₑ = 9 × 10⁻³¹ kg)

Which colour of the light has the longest wavelength?

The total energy of an electron in an atom in an orbit is^{-3}.4 eV. Its kinetic and potential energies are, respectively

An electron of mass m with an initial velocity \( \vec{v} = v_0 \hat{i} \) (\( v_0 > 0 \)) enters an electric field \( \vec{E} = -E_0 \hat{i} \) (\( E_0 = \text{constant} > 0 \)) at \( t = 0 \). If \( \lambda_0 \) is its de-Broglie wavelength at time t is

The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom is

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is

Given the value of Rydberg constant as 10⁷ m⁻¹, the wave number of the last line of the Balmer series in hydrogen spectrum will be

Consider 3^{rd} orbit of He⁺ (Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = 9 × 10⁹ constant, Z = 2 and h (Planck's Constant) = 6.6 × 10⁻³⁴ Js]

Hydrogen atom in ground state is excited by a monochromatic radiation of λ = 975 Å. Number of spectral lines in the resulting spectrum emitted will be

If the kinetic energy of the particle is increased to 16 times its previous value, the percentage change in the de-Broglie wavelength of the particle is

An electron in hydrogen atom makes a transition n₁ → n₂ where n₁ and n₂ are principal quantum numbers of the two states. Assuming Bohr’s model to be valid, the time period of the electron in the initial state is eight times that in the final state. The possible values of n₁ and n₂ are:

The de-Broglie wavelength of neutrons in thermal equilibrium at temperature T is: