Question

Which of the following arrangements of a wire clamped on two walls will cause an additional stress within the wire?

• A. A piece of wire clamped between two clamps is heated up
• B. A piece of wire clamped between two clamps is cooled down
• C. Both (a) and (b)
• D. Neither (a) nor (b)

Answer 1

The correct option is B A piece of wire clamped between two clamps is cooled down

Thermal stresses are induced when the expansion or contraction of an object is restricted by an external obstruction. Here, the contraction will be restricted by the clamping, so it will create additional stresses; but the expansion will not be restricted, and the wire will sag, hence no extra stress.