K.C.S.E Physics Q & A - MODEL 2014PP1QN07

K.C.S.E Physics Q & A - MODEL 2014PP1QN07

​Figure 4 shows a source of heat placed at equal distances from two identical flasks X and Y containing air. The surface of X is painted black while Y is clear

​X and Y are linked by a U-tube filled with water whose levels S and T are initially the same.
It is later observed that S falls while T rises. Explain this observation.

answer

•  Flask painted black absorbs more heat;
• causing more expansion of air above S than above T;
• hence S is pushed downwards and T upwards;