In the circuit shown the variable resistance is so adjusted that the ammeter reading is same in both the position $1$ and $2$ of the key. The reading of ammeter is $2A$. If $E = 20V$, then $x$ is :- ................... $\Omega$
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A cable of resistance $10\,\Omega $ carries electric power from a generator producing $250\, kW$ at $10000\, volt$, the power lost in the cable during transmission is ............. $kW$
When a current of $2\,A$ flows in a battery from negative to positive terminal, the potential difference across it is $12\,V$. If a current of $3\,A$ flows in the opposite direction potential difference across the terminals of the battery is $15\,V$, the emf of the battery is ............... $\mathrm{V}$
An electric kettle takes $4\, A$ current at $220\,V.$ How much time will it take to boil $1\,\, kg$ of water circuits are consequences of from temperature $20\,^o C\, ?$ The temperature of $(a)$ conservation of energy and electric charge boiling water is $100\,^o C.$ ............... $min$
A cell of $e.m.f.$ $1.5\,V$ having a finite internal resistance is connected to a load resistance of $2\,\Omega $. For maximum power transfer the internal resistance of the cell should be ............. $ohm$
In a potentiometer (see figure) a balance is obtained at a length of $400\ mm$ when using a known battery of emf $1.6\ V$. After removing this battery, another battery of unknown emf is used and balance is obtained at a length of $650\ mm.$ The emf of unknown battery is ............. $volt$
A potentiometer consists of two wires $AC$ and $CB$ of same material and of equal lengths but diameters in the ratio $3 : 1.$ Then the potential gradients on the two wires will be in the ratio :-