Modern Physics Mock Tests

A radioactive substance has a half-life of 5 years. The fraction of nuclei remaining after 15 years is:

A nuclear reaction converts 1 kg of mass completely into energy. The energy released is: (c = 3 × 10⁸ m/s)

In the Bohr model of the hydrogen atom, the radius of the nth orbit is proportional to:

The work function of a metal is 4.2 eV. Light of wavelength 200 nm is incident on the metal. What is the maximum kinetic energy of the emitted photoelectrons? (Take hc = 1240 eV·nm)

An electron and a proton have the same de Broglie wavelength. Which of the following statements is true?

The energy of a photon of wavelength 600 nm is approximately: (h = 6.63 × 10⁻³⁴ J·s, c = 3 × 10⁸ m/s)

In a photoelectric effect experiment, the work function of a metal is 2.0 eV. The threshold frequency is: (h = 6.63 × 10⁻³⁴ J·s, 1 eV = 1.6 × 10⁻¹⁹ J)

A radioactive sample has half-life T. The time taken for 7/8 of the sample to decay is: