Question asked by Filo student

4. $100\mathrm{W},220\mathrm{V}$ bulb is connected to $110\mathrm{V}$ source, 15 Calculate the power consumed by the bulb. [Roorkee 86] (Ans. $25\mathrm{W}$ ) 5. How many electrons flow per second through an electric bulb rated $220\mathrm{V},100\mathrm{W}$ ? [BIT Ranchi 98] (Ans. $2.84\times 10^{18}$ ) 6. An ammeter reads a current of $30\mathrm{A}$ when it is connected across the terminals of a cell of emf $1.5\mathrm{V}$. Neglecting the meter resistance, find the amount of heat produced in the battery in 10 seconds ? (Ans, $107.14\mathrm{cal}$ ) 7. A coil of resistance $100\Omega$ is connected across a battery of emf $6.0\mathrm{V}$. Assume that the heat developed in the coil is used to raise its temperature. If the thermal capacity of coil is $4.0{\mathrm{JK}}^{-1}$, how long would it take to raise the temperature of the coil by $15^{\circ }\mathrm{C}$ ? (Ans. $2.8\min$ ) 8. A generator is supplying power to a factory by cables of resistance $20\Omega$. If the generator is generating $50\mathrm{kW}$ power at $5000\mathrm{V}$, what is the power received by the factory ? [Punjab $96\mathrm{C}$ ] (Ans, $48\mathrm{kW}$ ) 9. Two bulbs are marked $220\mathrm{V},100\mathrm{W}$ and $220\mathrm{V}$, $50\mathrm{W}$ respectively. They are connected in series to $220\mathrm{V}$ mains. Find the ratio of heats generated in them. (Ans, 1:2) 10. In a house having $220\mathrm{V}$ line, the following appliances are working : (i) a $60\mathrm{W}$ bulb (ii) a $1000\mathrm{W}$ heater (iii) a $40\mathrm{W}$ radio. Calculate $(a)$ the current drawn by

Views: 5,123 students

Updated on: Jul 25, 2023