$ \Rightarrow $ $\%$ change in power $ = 2 \times $ $\%$ change in current
$=2 \times 1 = 2\% $
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$10\, Cells$, each of $emf$ $'E'$ and internal resistance $'r'$, are connected in series to a variable external resistance. Figure shows the variation of terminal potential difference of their combination with the current drawn from the combination.$Emf$ of each cell is ................ $V$
$A$ battery is of $\mathrm{emf}$ $E$ is being charged from a charger such that positive terminal of the battery is connected to terminal $A$ of charger and negative terminal of the battery is connected to terminal $B$ of charger. The internal resistance of the battery is $r$.
When two identical batteries of internal resistance $1 \Omega$ each are connected in series across a resistor $\mathrm{R}$, the rate of heat produced in $R$ is $J_1$. When the same batteries are connected in parallel across $R$, the rate is $\mathrm{J}_2$. If $\mathrm{J}_1=2.25 \mathrm{~J}_2$ then the value of $\mathrm{R}$ in $\Omega$ is
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A Copper $(Cu)$ rod of length $25\, {cm}$ and cross- sectional area $3\, {mm}^{2}$ is joined with a similar Aluminium $(Al)$ rod as shown in figure. Find the resistance of the combination between the ends $A$ and $B$ (in ${m} \Omega$)
(Take Resistivity of Copper $=1.7 \times 10^{-8}\, \Omega \,{m}$, Resistivity of Aluminium $=2.6 \times 10^{-8}\, \Omega \,{m}$ )
A wire of circular cross section has inner portion of radius $R$ made of material of resisitivity $\rho$ and is surrounded by an outer portion of thickness $R$ made of a material of double resisitivity. Find the resistance of length $l$ of such wire
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Three resistances of one ohm each are connected in parallel. Such connection is again connected with $\frac{2}{3}\,\Omega $ resistor in series. The resultant resistance will be ........... $\Omega$
There are three resistance coils of equal resistance. The maximum number of resistances you can obtain by connecting them in any manner you choose, being free to use any number of the coils in any way is