JEE Physics - MCQ Practice Questions

In a diffraction grating with 5000 lines/cm, the second order spectrum is observed at angle 30°. The wavelength of light is:

In a compound microscope, the objective has focal length 0.5 cm and eyepiece has focal length 5 cm. The distance between them is 20 cm. The magnifying power is approximately:

A concave mirror forms a real image 4 times larger than the object. The object is placed at distance u from the mirror. The focal length is:

In a Newton's rings experiment, dark fringe appears when the air gap thickness is:

In photoelectric effect, the stopping potential V₀ for a metal is 2V. If the frequency of incident light is doubled, the new stopping potential will be:

A 1 gram sample of a radioactive isotope with atomic mass 100 undergoes decay. Initial activity is 10¹⁵ Bq. The decay constant is approximately:

An electron and a proton have the same kinetic energy. The ratio of their de Broglie wavelengths (λₑ/λₚ) is:

A nucleus of mass number A and atomic number Z emits an alpha particle. The recoil kinetic energy of the daughter nucleus is 0.5 MeV. What is the kinetic energy of the alpha particle? (Assume non-relativistic motion)

The threshold energy for photodisintegration of a deuteron (D → p + n) by a photon is approximately 2.22 MeV. This means:

An excited hydrogen atom transitions from state with energy E₂ to state with energy E₁. The energy difference is hf. Which Bohr orbit transitions match this for hydrogen?

An electron in excited state of hydrogen atom has angular momentum 2ℏ. The principal quantum number n is:

The ratio of de Broglie wavelengths of an electron and a proton having same kinetic energy is:

A nucleus ²³⁸₉₂U undergoes two alpha decays and two beta decays. The final nucleus is:

The energy released in nuclear fusion of two deuterium nuclei to form ⁴He is approximately:

A free electron at rest absorbs a photon and immediately emits another photon. This process is not possible because:

Which decay process increases the neutron to proton ratio?

According to Heisenberg's uncertainty principle, if the uncertainty in position of an electron is 0.1 nm, the minimum uncertainty in velocity is approximately:

The ratio of speeds of an electron and an alpha particle having the same de Broglie wavelength is:

When ²³⁵U nucleus undergoes fission, the total mass defect is 0.1 u. The energy released is approximately:

An electron transitions from n=3 to n=1 in a hydrogen atom. How many distinct spectral lines can be observed from all possible transitions?