The thermal expansion coefficient of copper is about 1.7x10-5 / oC. A copper cable has a length of 20 m early in the morning, when the temperature is 15 oC. What is the change in it's length (Lnew-Lold) at noon, when the temperature is 25 oC?
1)1.7x10-4 m
2)3.4x10-4 m
3)3.4x10-3 m
4)-3.4x10-3 m