Physics Modern Physics questions from NEET UG 2008.
A p-n photodiode is made of a material with a band gap of $2.0 \mathrm{eV}$. The minimum frequency of the radiation that can be absorbed by the material is nearly
A p-n photodiode is made of a material with a band gap of $2.0 \mathrm{eV}$. The minimum frequency of the radiation that can be absorbed by the material is nearly
A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of $3 \times 10^6 \mathrm{~ms}^{-1}$. The velocity of the particle is (Mass of electron $=9.1 \times 10^{-31} \mathrm{~kg}$ )
A particle of mass $1 \mathrm{mg}$ has the same wavelength as an electron moving with a velocity of $3 \times 10^6 \mathrm{~ms}^{-1}$. The velocity of the particle is (mass of electron $=9.1 \times 10^{-31} \mathrm{~kg}$ )
If $M(A, Z), M_P$ and $M_n$ denote the masses of the nucleus ${ }_Z^A X$, proton and neutron respectively in units of $u\left(1 \mathrm{u}=931.5 \mathrm{MeV} / c^2\right)$ and $\mathrm{BE}$ represents its binding energy in $\mathrm{MeV}$, then
In the phenomenon of electric discharge through gases at low pressure, the coloured glow in the tube appears as a result of
In the phenomenon of electric discharge through gases at low pressure, the coloured glow in the tube appears as a result of
The circuit is equivalent to 
The circuit  is equivalent to
The ground state energy of hydrogen atom is $-13.6 \mathrm{eV}$. When its electron is in the first excited state, its excitation energy is
The ground state energy of hydrogen atom is $-13.6 \mathrm{eV}$. When its electron is in the first excited state, its excitation energy is
The work function of a surface of a photosensitive material is $6.2 \mathrm{eV}$. The wavelength of the incident radiation for which the stopping potential is $5 \mathrm{~V}$ lies in the
The work function of a surface of a photosensitive material is $6.2 \mathrm{eV}$. The wavelength of the incident radiation for which the stopping potential is $5 \mathrm{~V}$ lies in the
Two nuclei have their mass numbers in the ratio of $1: 3$. The ratio of their nuclear densities would be
Two nuclei have their mass numbers in the ratio of $1: 3$. The ratio of their nuclear densities would be
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 $\mathrm{X}_1$ to that of $X_2$ will be $\frac{1}{e}$ after a time
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 $\frac{1}{e}$ after a time