A straight wire of diameter $$0.4 \mathrm{~mm}$$ carrying a current of $$2 \mathrm{~A}$$ is replaced by another wire of 0.8 $$\mathrm{mm}$$ diameter carrying the same current. The magnetic field at distance $$(\mathrm{R})$$ from both the wires is 'B$$_1$$' and 'B$$_2$$' respectively. The relation between B$$_1$$ and B$$_2$$ is
In a CE transistor, a change of $$8.0 \mathrm{~mA}$$ in the emitter current produces a change of $$7.8 \mathrm{~mA}$$ in the collector current. What change in the base current is necessary to produce the same change in the collector current?
Water rises upto a height of $$4 \mathrm{~cm}$$ in a capillary tube. The lower end of the capillary tube is at a depth of $$8 \mathrm{~cm}$$ below the water level. The mouth pressure required to blow an air bubble at the lower end of the capillary will be '$$\mathrm{X}$$' $$\mathrm{cm}$$ of water, where $$\mathrm{X}$$ is equal to
The initial pressure and volume of a gas is '$$\mathrm{P}$$' and '$$\mathrm{V}$$' respectively. First by isothermal process gas is expanded to volume '$$9 \mathrm{~V}$$' and then by adiabatic process its volume is compressed to '$$\mathrm{V}$$' then its final pressure is (Ratio of specific heat at constant pressure to constant volume $$=\frac{3}{2}$$)