One $kg$ of water, at $20\,^oC$, is heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of $20\, \Omega $. The rms voltage in the mains is $200\, V$. Ignoring heat loss from the kettle, time taken for water to evaporate fully, is close to.......... $\min$ [Specific heat of water $= 4200\, J/kg\, ^oC$), Latent heat of water $= 2260\, k\,J/kg$]
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 copper rods are subjected to different potential difference. Compare the drift speed of electrons through them. Assume that all $3$ are at the same temperature.
The battery in the diagram is to be charged by the generator $G$. The generator has a terminal voltage of $120$ $\mathrm{volts}$ when the charging current is $10$ $\mathrm{amperes}.$ The battery has an $\mathrm{emf}$ of $100$ $\mathrm{volts}$ and an internal resistance of $1$ $\mathrm{ohm}.$ In order to charge the battery at $10$ $\mathrm{amperes}$ charging current, the resistance $R$ should be set at ................ $\Omega$
$A$ potentiometer wire has length $10\, m$ and resistance $10\,\Omega$ . It is connected to a battery of $EMF$ $11\, volt$ and internal resistance $1\, \Omega$ , then the potential gradient in the wire is ............... $V/m$
A piece of wire of resistance $4\, ohms$ is bent through $180^o$ at its mid point and the two halves are twisted together, then the resistance is ............ $ohms$
A galvanometer together with an unknown resistance in series is connected to two identical batteries each of $1.5\, V$. When the batteries are connected in series, the galvanometer records a current of $1\,A$, and when batteries are in parallel the current is $0.6\,A$. What is the internal resistance of the battery ?
A current of $2\,A$ flows through a wire of crosssectional area $25.0\,mm ^2$. The number of free electrons in a cubic meter are $2.0 \times 10^{28}$. The drift velocity of the electrons is $...............\times 10^{-6}\,ms ^{-1}$ (given, charge on electron $=1.6 \times 10^{-19}\,C$ )