A rectangular parallelopiped is measured as $1\,cm \times 1\,cm \times 100\,cm$. If its specific resistance is $3 \times 10^{-7}\,\Omega\,m$, then the resistance between its two opposite rectangular faces will be $..........x^{-7} \Omega$.
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Resistances $R_1$ and $R_2$ each $60\,\Omega$ are connected in series as shown in figure. The Potential difference between $A$ and $B$ is kept $120$ volt. Then what ............. $V$ will be the reading of voltmeter connected between the point $C$ and $D$ if resistance of voltmeter is $120\,\Omega .$
The current in a wire varies with time according to relation $I = 4 + 2t$. The quantity of charge which has passed through a crosssectionn of the wire during the time $t = 2\, s$ to $t = 6\, s$ will be .............. $\mathrm{C}$
A heating element has a resistance of $100\,\Omega $ at room temperature. When it is connected to a supply of $220\,V,$ a steady current of $2\,A$ passes in it and temperature is $500\,^oC$ more than room temperature. What is the temperature coefficient resistance of the heating element?
The charge flowing in a conductor varies with time as $Q = at -bt^2$. Then for current, which statement is incorrect.
$(A)$ decreases linearly with time
$(B)$ reaches a maximum and then decreases
$(C)$ fall to zero after time $t = a/2b$
$(D)$ changes at a rate $-2b$
Options :
A potentiometer having the potential gradient of $2\, mV/cm$ is used to measure the difference of potential across a resistance of $10 \,\Omega$. If a length of $50\, cm$ of the potentiometer wire is required to get the null point, the current passing through the $10 \,\Omega$ resistor is (in $mA$)