The equivalent resistance of the given circuit between the terminals $A$ and $B$ is :

A resistor dissipates $192 \mathrm{J}$ of energy in $1 \mathrm{s}$ when a current of $4 \mathrm{A}$ is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in $5 \mathrm{s}$ is _____________ $\mathrm{J}.$

The value of current in the $6 \mathrm{\Omega }$ resistance is:

A zener diode having zener voltage $8 V$ and power dissipation rating of $0.5 W$ is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance $R_p$ is _____$\mathrm{\Omega }.$

In the given figure switches $S_1$ and $S_2$ are in open condition. The resistance across $ab$ when the switches $S_1$ and $S_2$ are closed is ________$\mathrm{\Omega }.$

A Copper $\left(\mathrm{Cu}\right)$ rod of length $25 \mathrm{cm}$ and cross-sectional area $3{ \mathrm{mm}}^2$ is joined with a similar Aluminium $\left(\mathrm{Al}\right)$ rod as shown in figure. Find the resistance of the combination between the ends $A$ and $B.$

(Take resistivity of Copper $=1.7\times {10}^{-8} \mathrm{\Omega } \mathrm{m}$, Resistivity of aluminium $=2.6\times {10}^{-8} \mathrm{\Omega } \mathrm{m}$)