Modern Physics — JEE Main PYQs

The diagram shows the energy levels for an electron in a certain atom. Which transition shown represents the emission of a photon with the most energy?

If the kinetic energy of a free electron doubles, its de-Broglie wavelength changes by the factor

A nuclear transformation is denoted by $\mathrm{X}(\mathrm{n},\alpha {)}_3^7\mathrm{Li}$. Which of the following is the nucleus of element $X$?

A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal vs the frequency of the incident radiation gives straight line whose slope

The work function of a substance is 4.0 eV. Then longest wavelength of light that can cause photoelectron emission from this substance approximately

A nucleus disintegrates into two nuclear parts which have their velocities in the ratio $2:1$. The ratio of their nuclear sizes will be

The binding energy per nucleon of deuteron $\left({}_1^2\mathrm{H}\right)$ and helium nucleus $\left({}_2^4\mathrm{He}\right)$ is 1.1 MeV and 7 MeV respectively. If two deuteron nuclei react to form a single helium nucleus, then the energy released is

An $\alpha$-particle of energy 5 MeV is scattered through $180^{\circ }$ by a fixed uranium nucleus. The distance of the closest approach is of the order of