A. increases by two times
B. increases by four times
C. decreases by two times
D. decrease by four times
The kinetic energy of gas molecules is proportional to the square of their speed. If the speed of the gas molecules increases by a factor of two, the kinetic energy will increase by the square of two.
Thus, the kinetic energy will increase by four times.
The correct answer to the question: "If speed of gas molecules increases by twice on heating. What will be their kinetic energy?" is "increases by four times".
