$A$ straight wire of resistance $18 \Omega$ is bent in the form of an equilateral triangular loop. The effective resistance between any two vertices of the triangle is (in $Omega$)

$A$ heater $A$ gives out $300 \ W$ of heat when connected to a $200 \ V$ $d.c.$ supply. $A$ second heater $B$ gives out $600 \ W$ when connected to a $200 \ V$ $d.c.$ supply. If a series combination of the two heaters is connected to a $200 \ V$ $d.c.$ supply,the heat output will be ................. $W$.

Five identical resistors are initially arranged as shown in the figure by solid lines. If two identical resistors are added as shown by the dashed lines,the change in the equivalent resistance between the initial and final configurations is ....... $\Omega$.

$6 \Omega$ and $12 \Omega$ resistors are connected in parallel. This combination is connected in series with a $10 \text{ V}$ battery and a $6 \Omega$ resistor. What is the potential difference between the terminals of the $12 \Omega$ resistor (in $\text{ V}$)?

$10$ resistors,each of resistance $10\,\Omega$,can be connected to obtain maximum and minimum equivalent resistance. The ratio of maximum to minimum equivalent resistance will be $..........$.

If $400\; \Omega$ of resistance is made by adding four $100\; \Omega$ resistors of tolerance $5\%$ each,then the tolerance of the combination is .....$\%$