A silver wire has a resistance of 2.1 `Omega` at `27.5^(@)` C and a resistance of 2.8 `Omega` at `100^(@) C `. Determine the temperature coefficient of resistivity of silver.

Explanation

Here `R_(1) = 2.1 Omega, " " R_(2) = 2.7 Omega`
`t_(1) = 27.5^(@) C, t_(2) = 100^(@)C `
`alpha = ? `
`R_(2) = R_(1) [ 1 + alpha (t_(2) - t_(1)) ] `
`therefore (R_(2))/(R_(1)) = 1 + alpha [ t_(2) - t_(1)]`
`therefore (R_(2) - R_(1))/(R_(1)) = alpha [ t_(2) - t_(1)]`
`therefore alpha = (R_(2) - R_(1))/(R_(1) [t_(2) - t_(1)] )`
` = (2.7 - 2. 1)/(2.1(100- 27.5))`
`= (0.6)/(2.1 xx 72.5)`
= 0.00394
`= 0.0039^(@)C^(-1)`