Question

A bar of iron is 10 cm at 20°C. At 19°C it will be (are = 11 x 10-6/°C)

Answer 1

The answer is 3 ( 11 times 10-5 cm longer )

Answer 2

Answer:

HENCE (3) IS ANSWER

Explanation:

α =ΔL/(LO×Δ T)  or ΔL= α(LO×Δ T)

HERE ΔL  IS CHANGE IN  LENGTH, Lo is original length , α is coefficient of linear expansion , Δ T is change in temperature

α= 11 x 10 ^-6/°C , Δ T = 19-20 = -1°C

hence

ΔL= 11 x 10 ^-6×10×-1

     = - 11×10^-5

MINUS SIGN SHOWS SHORTER

HENCE (3) IS ANSWER