The pressure that has to be applied to the ends of a steel wire of length 10cm to keep its length constant when its temperature is raised by `100^@C` is : (For steel Young's modulus is `2xx10^11 Nm^-2` and coefficient of thermal expansion is `1.1xx10^-5K^_1`)

Explanation

Pressure, `P = (F)/(A)`
but `Y = (F//A)/((Delta l)/(l)) rArr (F)/(A) = Y (Delta l)/(l) =m Y alpha Delta t`
`because P = Y alpha Delta t = 2xx10^(11) xx 1.1xx10^(-5)xx10^(2) = 2.2xx10^(-8) Pa`