NEET Physics Thermal Properties Of Matter Radiation MCQs

A radioactive sample initially contains $N_0$ atoms. After three half-lives, what fraction of the original number of atoms remains undecayed?

Two radioactive isotopes X and Y have half-lives of $T_X$ and $T_Y$ respectively, with $T_X < T_Y$. If initially they have the same activity, which isotope will have a higher activity after a time $t > T_X$?

A radioactive nucleus undergoes successive disintegrations according to the following scheme: $A \xrightarrow{\alpha} B \xrightarrow{\beta} C \xrightarrow{\alpha} D$. If the mass number and atomic number of A are 180 and 72 respectively, what are the mass number and atomic number of D?

The decay constant of a radioactive substance is $\lambda$. After what time will the activity of the sample reduce to $1/e^2$ of its initial value?

In a nuclear reactor, which of the following is NOT a primary function of the moderator?

If the binding energy per nucleon of a nucleus with mass number A is $E_b$, what is the total binding energy of the nucleus?

A metal surface is illuminated by light of frequency $2 imes 10^{15}$ Hz. The work function of the metal is $5$ eV. Which of the following statements is correct regarding the emission of photoelectrons?

Which of the following electromagnetic radiations has the longest wavelength?

What is the energy of a photon with a wavelength of $500$ nm?

Which type of electromagnetic radiation is used in cancer therapy?