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Question
Calculate the value of the resistance which must be connected to a 15 ohm resistance to provide on effective resistance of 6 ohm.
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Solution
Resistance decreases in parallel combination. S let R resistance is connected to 15 Ω resistance parallel to make resultant 6 ohm.
Now, `1/6 = 1/15 + 1/"R"`
or `1/"R" = 1/6 - 1/15`
`= (5 - 2)/30 = 3/30 = 1/10`
∴ R = 10 Ω
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