A cylindrical conductor of diameter 0.1 mm carries a current of 90 mA . The current density ( in $\mathrm{Am}^{-2}$ ) is ( $\pi \approx 3$ )

A piece of copper is to be shaped into a conducting wire of maximum resistance. The suitable length and diameter are ......................and............................respectively.

In meter bridge experiment, with a standard resistance in the right gap and a resistance coil dipped in water (in a beaker) in the left gap, the balancing length obtained is ' $l$ '. If the temperature of water is increased, the new balancing

The power dissipated in $3 \Omega$ resistance in the following circuit is