Question

A galvanometer of resistance 50 ohms which gives a full scale deflection for 1M.A is to be adapted to measure current of up to 5A.-calculate tht resistance of the resistor required.- if this resistor is made of a material of cross-sectional area 4*10^-4cm2 and resistivity 2*10^-6cm2 calculate it's length​

Answer 1

Step-by-step explanation:

R = (50 ohms x 5A) / 1mA = 250 ohms

The resistance of the resistor is 250 ohms.

The resistivity (ρ) = 2 x 10^-6 cm^2

The cross-sectional area (A) = 4 x 10^-4 cm^2

Therefore, the length (l) = (ρ x R) / A

l = (2 x 10^-6 cm^2 x 250 ohms) / (4 x 10^-4 cm^2)

l = 1.25 cm