A coil has resistance 30 O and inductive reactance 20 O at 50 Hz frequency. If an AC source 200 V, 100 Hz, is connected across the coil, the current in the coil will be

4.0 A

8.0 A

$fraction numerator 20 over denominator square root of 13 end fraction space A$

2.0 A

Solution

4.0 A

If space straight omega space equals space 50 space straight x space 2 straight pi space then space ωL space equals space 20 space straight capital omega similarly space straight omega apostrophe space equals space 100 space straight x space 2 straight pi space then space straight omega apostrophe space straight L space equals space 40 space straight capital omega straight i space equals space 200 over straight z space equals space fraction numerator 200 over denominator square root of straight R squared plus left parenthesis straight omega apostrophe straight L right parenthesis squared end root end fraction equals space fraction numerator 200 over denominator square root of left parenthesis 30 right parenthesis squared plus left parenthesis 40 right parenthesis squared end root end fraction space equals space 4 space straight A

Some More Questions From Units and Measurement Chapter

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