JEE Physics - MCQ Practice Questions

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:

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:

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

An electron in the first excited state of hydrogen atom (n=2) transitions to ground state (n=1). The wavelength of emitted photon is approximately:

The de Broglie wavelength of an electron with kinetic energy 50 eV is:

In Compton scattering, a photon collides with a free electron at rest. Which quantity always increases?

The activity of a radioactive sample decreases from 8000 Bq to 1000 Bq in 20 hours. The half-life of the sample is:

In a nuclear reactor, control rods are used to absorb neutrons. Which isotope is commonly used in control rods?

A radioactive nucleus ₆₀₂₇Co undergoes beta-plus decay. The daughter nucleus is:

The threshold frequency for photoelectric effect in a metal is 6 × 10¹⁴ Hz. The work function of the metal is:

According to the uncertainty principle, if the position of an electron is known with uncertainty Δx = 10⁻¹⁰ m, the minimum uncertainty in momentum is:

The intensity of characteristic X-rays depends on:

A photon of wavelength 100 pm strikes a stationary free electron. After Compton scattering at an angle of 60°, the wavelength of the scattered photon is found to be 102.4 pm. What is the kinetic energy of the recoil electron? (Given: h = 6.63 × 10⁻³⁴ J·s, c = 3 × 10⁸ m/s, mₑ = 9.1 × 10⁻³¹ kg)

In an n-type semiconductor, the Fermi level lies:

The conductivity of a semiconductor increases with temperature because:

The intrinsic carrier concentration ni in a semiconductor is given by: ni = √(NcNv)exp(-Eg/2kT). What does Nc represent?