Ratio of thermal energy released in two resistors R and 3R connected in parallel in an electric circuit is :
The resistance of a wire is 5 $$\Omega$$. It's new resistance in ohm if stretched to 5 times of it's original length will be :
A uniform metallic wire carries a current 2 A, when 3.4 V battery is connected across it. The mass of uniform metallic wire is 8.92 $$\times$$ 10$$^{-3}$$ kg, density is 8.92 $$\times$$ 10$$^{3}$$ kg/m$$^3$$ and resistivity is 1.7 $$\times$$ 10$$^{-8}~\Omega$$-$$\mathrm{m}$$. The length of wire is :
A cell of emf 90 V is connected across series combination of two resistors each of 100$$\Omega$$ resistance. A voltmeter of resistance 400$$\Omega$$ is used to measure the potential difference across each resistor. The reading of the voltmeter will be :