NEET Modern Physics MCQs & PYQs

In the given reaction \[_{Z}X^{A}\longrightarrow _{Z}Y^{A’}+n\alpha+n’\beta\]. The ratio (Z/A) will be equal to.

When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectron and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I, the number of emitted electrons and their maximum kinetic energy are respectively : (Assume frequency of radiation to be constant)

A beam of fast moving α-particles was directed towards a thin film of gold. The part A’, B’ and C’ of the transmitted and reflected beams corresponding to the incident parts A, B and C of the beam are shown in the adjoining diagram. The number of α-particle in :

When the energy of the incident radiation is increased by 20%, the kinetic energy of the
photoelectrons emitted from a metal surface increased from 0.5eV to 0.8eV. The work
function of the metal is :

The de Broglie wavelength of an electron moving with a velocity

\[1.5\times 10^{8}m/s\] is equal to that of a photon. The ratio of the kinetic energy of the electron to the energy of the photon is :

A 200 W sodium street lamp emits yellow light of wavelength 0.6μm. Assuming it to be 25%
efficent converting electrical energy to light, the number of photons of yellow light it emits per
second is :

The ratio of wavelength of deutron and proton accelerated through the same potential difference will be :

Fusion reaction takes place at high temperature because :

In radioactive decay process, the negatively charged emitted β – particles are :

If the binding energy per nucleon of deuteron is 1.115 MeV, its mass defect in atomic mass unit is :