The deflection in a moving coil galvanometer falls from 50 to 10 divisions when a shunt of 12 Ohms is connected across it. The resistance of the galvanometer coil is
A galvanometer of resistance 1O Ohms gives full-scale deflection when I mA current passes through it. The resistance required to convert it into a voltmeter reading up to 2.5 V is
The driver cell of a potentiometer has an emf of 2 V and negligible internal resistance. The potentiometer wire has a resistance of 5 Ohms and is I m long. The resistance which must be coimected in series with the wire so as to have a potential difference of 5 mV across the whole wire is
An electric kettle has two coils. When one coil is connected to the ac mains, the water in the kettle boils in 10 minutes, When the other coil is used, thc same quantity of water takes 15 minutes to boil. How long will it take for the same quantity of water to boil if the two coils are connected in parallel?
An electric bulb has a rating of 500W, 100 V. It is used in a circuit having a 200 V supply. What resistance must be connected in series with the bulb so that it delivers 500 W?