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To measure the temperature coefficient of resistivity $\alpha$ of a semiconductor, an electrical arrangement shown in the figure is prepared. The arm BC is made up of the semiconductor. The experiment is being conducted at $25^{\circ} \mathrm{C}$ and resistance of the semiconductor arm is $3 \mathrm{~m} \Omega$. Arm BC is cooled at a constant rate of $2^{\circ} \mathrm{C} / \mathrm{s}$. If the galvanometer $\mathrm{G}$ shows no deflection after $10 \mathrm{~s}$, then $\alpha$ is :
$10$ wires (same length, same area, same material) are connected in parallel and each has $1$ $\Omega$ resistance, then the equivalent resistance will be .............. $\Omega$
Two resistors are connected $(a)$ in series $(b)$ in parallel. The equivalent resistance in the two cases are $9$ $ohm$ and $2$ $ohm$ respectively. Then the resistances of the component resistors are
Power dissipated across the $8\,\Omega $ resistor in the circuit shown here is $2\, watt$. The power dissipated in watt units across the $3\,\Omega $ resistor is
In an experiment to measure the internal resistance of a cell by potentiometer, it is found that the balance point is at a length of $2\,m$ when the cell is shunted by a $5\,\Omega $ resistance; and is at a length of $3\,m$ when the cell is shunted by a $10\,\Omega $ resistance. The internal resistance of the cell is, then ................ $\Omega $
When a potential difference $V$ is applied across a wire of resistance $R$, it dissipates energy at a rate $W$. If the wire is cut into two halves and these halves are connected mutually parallel across the same supply, the same supply, the energy dissipation rate will become:
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 $\alpha=2 \times 10^{-4} /{ }^{\circ} \mathrm{C}$ )