JEE Physics - MCQ Practice Questions

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):

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: