Question

A square is cut out of a copper sheet. Two straight scratches on the surface of the square intersect forming an angle. The square is heated uniformly. As a result, the angle between the scratches

a) increases
b) decreases
c) stays the same
d) The answer depends on whether θ is an acute or obtuse angle.

Answer 1

(c) Stay the same

Explanation:

Final angle will be same as initial angle. But length of lines will increase in both direction proportionally.

However any normal curve(closed or open ) will remain proportional to initial one. It is like a Zooming or magnifying of object.