# Thermal Expansion

The law of thermal expansion is

$Delta(L)/L0 = alpha*Delta(T)$

where L is the length, T the temperature in Celsius deg and  delta are differences.

$Delta(L) = alpha*L0*Delta(T)$

now one has for the angle $theta$

$tan(theta) = [Delta(L1) – Delta(L2)]/a = [Delta(T1)-Delta(T2)]*alpha*L0/a$

$theta = arctan(14*(10^{-6})*2*(Delta(T1) – Delta(T2))/1.2) =$

$=arctan[2.33*(10^{-5})*(Delta(T1)-Delta(T2))]$

$theta = arctan(2.33*10^{-5}*30) =arctan(7*10^{-4}) = 4*10^{-2} degree = 7*10^{-4} rad$