A cell of $emf$ $E$ and internal resistance $r$ is connected in series with an external resistacne $nr.$ Then, the ratio of the terminal potential difference to $emf$ is
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Three resistances of magnitude $2$, $3$ and $5$ $ohm$ are connected in parallel to a battery of $10\, volts$ and of negligible resistance. The potential difference across $3\,\Omega $ resistance will be ............... $volts$
A cylindrical resistance is connected across battery $\varepsilon $ . Cylinder has uniform free electron density, mid part of cylinder has larger radius as shown in figure. Then $V_d$ (drift velocity) $V/S$ (distance across the length of the resistance)
The resistance of a wire is $R$. It is bent at the middle by $180^{\circ}$ and both the ends are twisted together to make a shorter wire. The resistance of the new wire is
The resistance of a wire is ${10^{ - 6}}\,\Omega $ per meter. It is bend in the form of a circle of diameter $2\,m$. A wire of the same material is connected across its diameter. The total resistance across its diameter $AB$ will be
Two $220\; V , 100 \;W$ bulbs are connected first in series and then in parallel. Each time the combination is connected to a $220 \;V \;AC$ supply line. The power drawn by the combination in each case respectively will be
Dimensions of a block are $1\,cm \times 1\,cm \times 100\,cm$. If specific resistance of its material is $3 \times {10^{ - 7}}\,ohm - m$, the resistance between the square faces is
An electric toaster has resistance of $60\ \Omega$ at room temperature $\left(27^{\circ} \mathrm{C}\right)$. The toaster is connected to a $220 \mathrm{~V}$ supply. If the current flowing through it reaches $2.75 \mathrm{~A}$, the temperature attained by toaster is around : (if $\alpha=2 \times 10^{-4} /{ }^{\circ} \mathrm{C}$ )