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Two resistance connected in parallel acr...

Two resistance connected in parallel across a cell of negligible internal resistance, use 4.5 times the power that they would use, when in series across the same cell. If one of the resistance is 8ohm, the other is:-

A

`8Omega`

B

`12Omega`

C

`16Omega`

D

`36Omega`

Text Solution

Verified by Experts

`P_(p)=(V^(2)(R_(1)+R_(2)))/(R_(1)R_(2))`
`P_(s)=(V^(2))/(R_(1)+R_(2))`
`P_(P)=4.5Ps`
`(R_(1)+R_(2))/(R_(1)R_(2))=(9)/(2(R_(1)+R_(2))) because (R_(1)=8.2)`
`(8+R_(2))/(8R_(2))=36 R_(2)`
`R_(2)^(2)-20R_(2)+ 6 4=0`
`R_(2)=16,4`
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