AIPMT 2008 Main Mock Test

The work function of a surface of a photosensitive material is $6.2\text{eV}$. The wavelength of the incident radiation for which the stopping potential is $5\text{V}$ lies in the:

A particle of mass $1\text{mg}$ has the same wavelength as an electron moving with a velocity of $3\times 10^6{\text{ms}}^{-1}$. The velocity of the particle is ($mass$ $of$ $electron=9.1\times 10^{-31}\text{kg}$):

The ground state energy of hydrogen atom is $-13.6\text{eV}$. When its electron is in the first excited state, its excitation energy is:

Two radioactive materials $X_1$ and $X_2$ have decay constants $5\lambda$ and $\lambda$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of $X_1$ to that of $X_2$ will be $1/e$ after a time:

Two nuclei have their mass numbers in the ratio of $1:3$. The ratio of their nuclear densities would be: