Physics Modern Physics questions from JEE Main 2006.
A solid which is transparent to visible light and whose conductivity increases with temperature is formed by
An alpha nucleus of energy $\frac{1}{2} m v^2$ bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to
If the binding energy per nucleon in ${ }_3^7 \mathrm{Li}$ and ${ }_2^4 \mathrm{He}$ nuclei are $5.60 \mathrm{MeV}$ and $7.06 \mathrm{MeV}$ respectively, then in the reaction $\mathrm{p}+{ }_3^7 \mathrm{Li} \rightarrow 2{ }_2^4 \mathrm{He}$ energy of proton must be
If the lattice constant of this semiconductor is decreased, then which of the following is correct? 
If the ratio of the concentration of electrons that of holes in a semiconductor is $\frac{7}{5}$ and the ratio of currents is $\frac{7}{4}$, then what is the ratio of their drift velocities?
In the following, which one of the diodes is reverse biased?
The anode voltage of a photocell is kept fixed. The wavelength $\lambda$ of the light falling on the cathode is gradually changed. The plate current $\mathrm{I}$ of the photocell varies as follows :
The circuit has two oppositely connect ideal diodes in parallel. What is the current following in the circuit? 
The threshold frequency for a metallic surface corresponds to an energy of $6.2 \mathrm{eV}$, and the stopping potential for a radiation incident on this surface $5 \mathrm{~V}$. The incident radiation lies in
The time by a photoelectron to come out after the photon strikes is approximately
When ${ }_3 \mathrm{Li}^{\prime}$ nuclei are bombarded by protons, and the resultant nuclei are ${ }_4 \mathrm{Be}^8$, the emitted particles will be