Question

Figure shows the variation in temperature with time when some wax cools from the liquid phase to the solid phase. In which part of the curve, the wax was is in liquid phase?

• A. PQ
• B. QS
• C. ST
• D. none of the above

Answer 1

The correct option is A PQ

The graph shows a horizontal line SQ i.e. temperature of substance remains constant with time. Thus SQ must be a phase transformation as temperature of substance remains constant during phase transformation.

Hence PQ represents the substance in liquid phase since the graph shows the variation of cooling of wax from liquid to solid phase.