A parallel combination of three resistors takes 7.5A from a supply of 30V. it two resistors are 10ohm and 12ohm,find the third resistor.
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A parallel combination of three resistors takes 7.5A from a supply of 30V. it two resistors are 10ohm and 12ohm,find the third resistor.
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Answer:
ITotal = 7.5A
V = 30V
(V/I) = {(30)/(7.5)} = 4
i.e. RTotal = 4Ω
Let third resistor be R.
hence (1/4) = (1/10) + (1/12) + (1/R)
∴ (1/R) = (1/4) – (1/10) – (1/12)
∴ (1/R) = {(15 – 6 – 5)/(60)}
∴ (1/R) = (4/60) = (1/15)
R = 15Ω
Answer:
The correct option (B) 15Ω
Explanation:
Total = 7.5A V = 30V (V/I) = {(30)/(7.5)} = 4 i.e. RTotal = 4Ω Let third resistor be R. hence (1/4) = (1/10) + (1/12) + (1/R) ∴ (1/R) = (1/4) – (1/10) – (1/12) ∴ (1/R) = {(15 – 6 – 5)/(60)} ∴ (1/R) = (4/60) = (1/15) R = 15Ω