JAMB - Physics (2018 - No. 73)
Palm oil from a bottle flows out more easily after it has been heated because the
Molecules do not increase speed during the heating
Viscosity of oil is reduced
Oil molecules force each other out
Adhesion between the oil molecules and those of the bottle is increased
Explanation
If a liquid is heated the particles are given more energy and move faster and faster expanding the liquid.The result is that liquids show a reduction in viscosity with increasing temperature. With high temperatures, viscosity increases in gases and decreases in liquids, the drag force will do the same.