Final answer:
The change in length of a nickel bar can be calculated using its thermal expansion coefficient and the change in temperature.
Step-by-step explanation:
The change in length of a material due to temperature is determined by its thermal expansion coefficient. In the case of the nickel bar, we need to find its change in length when heated from 10°C to 300°C.
The formula for linear thermal expansion is:
ΔL = αLΔT
Where ΔL is the change in length, α is the thermal expansion coefficient, L is the original length, and ΔT is the change in temperature.
Since we know the original length (30 meters) and the change in temperature (300°C - 10°C = 290°C), we can calculate the new length using the given value for the thermal expansion coefficient of nickel.