An electric lamp which runs at 80 volt d.c. and consumes 10 ampere is connected to 100 volt, 50 Hz a.c. mains. Calculate the inductance of the choke required.

Options

A. `0.01H`
B. `0.02H`
C. `0.04H`
D. `0.08H`

Answer

B

Explanation

`R = (V)/(i) = (80)/(10) = 8 Omega`
`I = 10A`
`I = (V)/(Z) implies 10 = (100)/(Z)`
`Z =10 Omega`
`Z^(2)=R^(2) + X_(L)^(2) implies (10)^(2) = (8)^(2) + X_(L)^(2)`
`X_(L) =6 Omega`
` OmegaL = 2pi f L =6 Omega`
`2 pi xx 50 L =6 implies L = (6)/(100 pi) = (6)/(100 xx 3) = 0.02 H`
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