JEE Physics - MCQ Practice Questions

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

The threshold frequency for a metal is f₀. If light of frequency 2f₀ is incident, the maximum kinetic energy of photoelectrons is:

A charged particle is accelerated through a potential difference of 100V. Its de Broglie wavelength is λ₁. If accelerated through 400V, the wavelength becomes λ₂. The ratio λ₁/λ₂ is:

The activity of a radioactive sample decreases by 50% in 1 hour. Its half-life is:

The work function of a metal is 2.3 eV. The metal will exhibit photoelectric effect with light of wavelength:

The energy of an α-particle in the ground state of hydrogen-like atom (Z=2) compared to ground state of hydrogen is:

The characteristic X-ray spectrum is produced due to:

According to Heisenberg's uncertainty principle, if the uncertainty in position (Δx) is zero, then uncertainty in momentum (Δp) will be:

The pair production process requires a minimum photon energy of:

The de Broglie wavelength of a neutron moving with kinetic energy 1 eV is approximately:

In the photoelectric effect, the stopping potential V₀ for a metal is 2 V when light of wavelength 400 nm is incident. The work function of the metal is approximately:

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: