दो तारों के प्रतिरोध `R_(1)` तथा `R_(2)` एवं प्रतिरोध ताप गुणांक क्रमश: `alpha_(1)` तथा `alpha_(2)` हैं। इन्हें श्रेणीक्रम में जोड़ा गया है। तो संयोजन का प्रभावी प्रतिरोध ताप गुणांक होगा

Options

A. `(alpha_(1)+alpha_(2))/(2)`
B. `sqrt(alpha_(1)alpha_(2))`
C. `(alpha_(1)R_(1)+alpha_(2)R_(2))/(R_(1)+R_(2))`
D. `(sqrt(R_(1)R_(2)alpha_(1)alpha_(2)))/(sqrt(R_(1)^(2)+R_(1)^(2)))`

Answer

C

Explanation

`R_(t_(1))=R_(1)(1+alpha_(1)t)` एवं `R_(t_(2))=R_(t_(2))=R_(2)(1+alpha_(2)t)`
एवं `R_(eq)=R_(t_(1))+R_(t_(2)) rArr R_(eq)=R_(1)+R_(2)+(R_(1)alpha_(1)+R_(2)alpha_(2))t`
`rArr R_(eq)=(R_(1)+R_(2)){1+((R_(1)alpha_(1)+R_(2)alpha_(2))/(R_(1)+R_(2))).t}`
अत: `alpha_(eff)=(R_(1)alpha_(1)+R_(2)alpha_(2))/(R_(1)+R_(2))`