The current flowing through a coil of resistance `900 Omega` is to be reduced by `90%`. What should be the resistance of shunt to be used ?

2 amp current flowing through a wire produces 10 calories ofheat in 20 seconds.What is the resistance of the wire ?

A current of 10 Ampere flows through a coil of resistance 100 ohm. A second coil of resistance R ohm is connected across the first coil so that the current through the second coil is 8 amperes. Then the value of R in ohms is