Question

determine the resistance of a coil whose mean diameter is 2.5cm having 100 turns of manganin wire of 0.0648 cm dia. the specific resistance of manganin wire is 42/1000000 ohm-cm​

Answer 1

Answer:

(1) Resistance of the coil R= p×L/A

(2) Given p= 42/1000000 ohm-cm

(3) length of the wire in the coil = length of each turn× total number of turns

(4)given mean diameter of the coil = 2.5 cm, hence radius = 1.25 cm and circumference 2×π×R=2×22/7×1.25=7.85 cm

(5) length of the wire = circumference× No of turns = 7.85 × 100=785 cm

(6)cross sectional area of the wire= π×d^2/4 = π×0.0648^2/4=3.297 cm^2

(7)total resistance of the coil=42/1000000×785/3.29=0.01 Ohm