Quick question on thermal expansion.

[marmot]

Homework Statement

In a bimetallic strip of brass and copper which curls when heated, the brass is on the inside of the curve.

True or false?

Homework Equations

deltaL=alpha*Lo*deltaT

The Attempt at a Solution

It is false but I do not get why. Brass has a higher coefficient of linear expansion so if it is in the inside, I suppose it will expand faster than the copper causing stress in the copper to curl?

 

[Delphi51]

Brass expands more, so the strips will bend so the brass strip is on the outside. If it bent so far as to form a circle, you could say greater radius, greater circumference.

 

[thomate1]

Your understanding is correct. The statement is false because the brass, which has a higher coefficient of linear expansion, will expand more than the copper and therefore will be on the outside of the curve. This is because the brass will experience more expansion and will push against the copper, causing it to curl. This is known as the thermal gradient and is a result of the difference in thermal expansion between the two materials.