JEE Physics - MCQ Practice Questions

A photon of energy 15 eV is incident on a hydrogen atom in ground state. What is the maximum number of energy levels the electron can reach?

Which of the following statements about photoelectric effect is correct?

A free electron at rest absorbs a photon and immediately emits another photon. This process is not possible because:

The de Broglie wavelength of a neutron at room temperature (T = 300 K) is approximately:

In beta decay of ¹⁴₆C, the atomic number of daughter nucleus is:

The half-life of a radioactive substance is 10 days. What fraction of the original sample remains after 30 days?

Two alpha particles separated by distance r repel each other with force F. If they are separated by distance r/2, the new force is:

In Bohr's model, the angular momentum of electron in nth orbit is:

An electron transitions from n=3 to n=1 in hydrogen atom. The frequency of emitted photon is (R = 1.097×10⁷ m⁻¹):

The nuclear radius of a nucleus with mass number A is given by R = R₀A^($\frac{1}{3}$), where R₀ ≈ 1.2 fm. For ⁸⁸₃₈Sr, the nuclear radius is approximately:

The decay constant λ of a radioactive substance and its half-life t₁/₂ are related by:

An electron and a proton have the same kinetic energy. The ratio of their de Broglie wavelengths is:

Which decay process increases the neutron to proton ratio?

The stopping potential in photoelectric effect for a metal with work function 2.5 eV when illuminated by light of wavelength 400 nm is approximately:

In nuclear fission of ²³⁵U, approximately 200 MeV energy is released. The mass defect in this reaction is approximately:

According to Heisenberg's uncertainty principle, if the uncertainty in position of an electron is 0.1 nm, the minimum uncertainty in velocity is approximately:

The characteristic X-rays are produced when:

A nucleus ⁹⁴₃₈Sr undergoes beta-minus decay followed by another beta-minus decay. The final nucleus is:

The ratio of speeds of an electron and an alpha particle having the same de Broglie wavelength is:

A photon of frequency 6 × 10¹⁵ Hz is incident on a metal surface with work function 2 eV. What is the maximum kinetic energy of the ejected photoelectron? (h = 4.14 × 10⁻¹⁵ eV·s)