JEE Physics - MCQ Practice Questions

Two radioactive nuclei A and B have decay constants λₐ and λᵦ respectively, where λₐ = 2λᵦ. Initially, both have the same number of nuclei. The ratio of their half-lives (t₁/₂ₐ : t₁/₂ᵦ) is:

An electron transitions from n=3 to n=1 in a hydrogen atom. The ratio of wavelengths emitted to that expected for Lyman alpha (n=2 to n=1) is:

In Compton scattering, a photon of wavelength λ₀ collides with a stationary electron. After scattering at angle θ = 90°, the wavelength becomes λ. The relationship is:

A radioactive sample has a half-life of 10 days. After how many days will 93.75% of the sample decay?

The frequency of K-alpha X-ray for a target material depends on:

The cutoff wavelength (λ₀) in X-ray spectrum produced by deceleration of electrons is determined by:

In a cathode ray tube with accelerating potential V, electrons reach the anode with kinetic energy. If V is doubled, the maximum frequency of X-rays produced will:

A hydrogen atom transitions from n=4 to n=2 state. The wavelength of emitted photon is approximately:

The binding energy per nucleon for ⁵⁶Fe is maximum among all nuclei. This suggests that:

A radioactive element has 75% of its original mass remaining after 6 hours. What is its half-life?

The de Broglie wavelength of an electron accelerated through a potential difference of 100 V is approximately:

The work function of a metal is 3 eV. What is the threshold frequency for photoelectric emission?

In a hydrogen atom, the ground state energy is -13.6 eV. What is the energy required to ionize from n=3?

When a moving electron is stopped completely in matter, the kinetic energy is converted to:

In X-ray production, the minimum wavelength of continuous X-ray spectrum depends on:

In Compton effect, the wavelength shift depends on:

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?

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

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:

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