Question

Assertion :Galvanometer cannot as such be used as an ammeter to measure the value of the current in a given circuit
Reason : Galvanometer gives a full-scale deflection for a current of the order of micro ampere.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

Galvanometer is a very sensitive device, it gives a full-scale deflection for current of the order of micro ampere. Also for measuring current the galvanometer has to be connected in series, and as it has a large resistance, this will change the value of the current in the circuit. To overcome these difficulties one attaches a small resistance called shunt resistance in parallel with the galvanometer coil