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

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 ?

The elctric current flowing in a wire in the direction B to A is decreasing. What is the direction of induced current in the metallic loop kept above it?