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A step-down transfdormer connected to ma...

A step-down transfdormer connected to main supply of 220 V is made to operate 11 V, 88W lamp. Calculate (i) Transformation ration and (ii) Current in the primary.

Text Solution

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Given : `V_(p)=20V,V_(s)=11V,`
Output power = 88 W
To find : `I_(p)=?`
Transformer Ratio K = ?
Output power `=V_(s)I_(s)`
`88=11xxI_(s)`
`I_(s)=(88)/(11)=8A`
`(V_(s))/(V_(p))=(I_(p))/(I)`
`I_(p)=(I_(s)xxV_(s))/(V_(p))=(8xx11)/(220)=(88)/(220)=0.4A.`
`(V_(s))/(V_(p))=k`
`k=(11)/(220)=(1)/(20).`
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