Question

A coil having self-inductance of 0.7 H and resistance of 165 Ω is connected to an a.c. source of 

275V,50Hz. If π = `22/7`

Calculate:
(i) Reactance of the coil
(ii) Impedance of the coil ‘
(iii) Current flowing through the coil 

Answer 1

l = 0.7 H , R = 165 Ω , V = 275 V

f = 50 Hz , π = `22/7`

(i) X_L = 2 π f L   [X_L = reactance]

`= 2 xx 22/7 xx 50 xx 0.7 = 220 Omega`

(ii) Impedance (Z) of the coil

Z = `sqrt("R"^2 +(2pi  "f"  "L")^2) = sqrt((165)^2 + (220)^2) = sqrt75625 = 275 Omega`

(iii) Current (I) in the coil
= `"V"/"Z" = (275"V")/(275Omega) = 1"A"`