CBSE Class 12-science Answered
The magnetic field produced by current carrying conductor A in the vicinity of conductor B is verically downward. By Fleming left hand rule, the force experienced by any element of conductor B will be away from A. Thus two parallel straight conductors carrying opposite currents repel each other.
OR
A galvanometer can be used as such to measure current due to following two reasons.
(i) A galvanometer has a finite large resistance and is connected in series in the circuit, so it will increase the resistance of circuit and hence change the value of current in the circuit.
(ii) A galvanometer is a very sensitive device, it gives a full scale deflection for the current of the order of microampere, hence if connected as such it will not measure current of the order of ampere.