Question

What is the resistance of a coil which draws a current of (a) 50 mA and (b) 200 μA from a 120 V supply?

Answer 1

Hi there !!

a) 1mA = 10⁻³ A
50 mA = 0.05 A

Potential difference = V = 120 V
Current = I = 0.05 A
Resistance = R

V = IR

R = V / I
    = 120 / 0.05 = 2400 Ω

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b)
1μA = 10⁻⁶ A
200μA = 0.0002 A

Potential difference = V = 120 V
Current = I = 0.0002 A
Resistance = R

R = V / I
   = 120 / 0.0002
   = 600000Ω

Answer 2

Since V=I×R
→R=V/I
Using the given values
1→R=2400ohm
2→R=600ohm