A miliammeter of resistance 5 ohms gives a full scale deflection for a current of 15 mA. If the milliammeter is to be used to measure currents upto 1.5 A the size of the resistance that must be attached to the milliammeter is ?

A galvanometer having a resistance of 50Ω gives a full scale deflection for a current of 0.05 A. The length in meter of a resistance wire of area of cross section 3×10^−3 cm^2 that can be used to convert the galvanometer into an ammeter which can read a maximum of 5A current is [specific resistance of the wire =5×10^−7 Ωm]

A galvanometer having a coil resistance 120 Omega shows full scale deflection for a current of 2.5 mA. How would you convert it into an ammeter of range 0 to 75A?

A galvanometer coil has a resistance of 10Omega and the meter shows full scale deflection for a current of 2.5 mA. How will you convery the metre into an ammeter of range 0 to 4A.

A galvanometer has an internal resistance of 1.0 ohm. It gives maximum deflection for current of 50 mA. Show how it can be converted into (i) a voltmeter with a maximum reading a of 2.5 volts, (ii) an ammeter with a maximum reading of 2.5 A.

An electric iron of resistance 20Omega takes a current of 5A. Calculate the heat developed in 30s.

battery gives a current of 0.5A with an external resistor of 12 Omega and.0.25A with resistor of 25 Omega Calculate the internal resistance of the battery.