The coefficient of real expension of mercury is `18 xx 10 ^(-5//@)C`.The thermometer bulb has a volume of `10^(-6) m^(3)` and cross- section of the steam is `0.002 cm^(2)`. Assuming that the bulb is filled with mercury at `0^(@)C` , the length of the mercury column at `100^(@)C` will be

Options

A. 9 cm
B. 18 cm
C. 9 mm
D. 18 mm

Answer

A

Explanation

Coefficient of real expansion, `gamma=(Deltav)/(v(Deltat)`
` implies Deltav=vgamma(Deltat)=10^(-6)xx18xx10^(-5)xx100=18xx10^(-9)m^(3)`
`Length = ("increase in volume")/("Area of cross section")`
`therefore l=(18xx10^(-9))/(0.002)=(18xx10^(_9)xx(10^(_2))^(3))/(0.002)=9cm`