D'Arsonval movement : how can i find the resistance if only the current is given

a 1 ohm resistor is connected in paralle with a d'Arsonval movement having a full scale deflection of 1 mA.
if a 40 mA current produces a deflection that is 80% of full scale , determine the resistance of the d'Arsonval movement

thanks in advance

80% of 1 mA = 0.8mA of current through the meter

40mA - 0.8mA = 39.9mA flows through the 1 ohm resistor

Voltage developed then is 39.9 mA * 1 Ohm = 39.2 mV

d'Arsonval resistance then = 39.2 mV / 0.8 mA = 49 ohms

Hope this helps,

Newton1Law

Jsj