Question

Which phenomenon occurs during the following change?
Solid wax left out in the sun
(A) Sublimation
(B) Melting
(C) Condensation
(D) Evaporation

Answer 1

Hint: The given situation where a piece of solid wax is left in the sun, involves absorption of energy by the piece of wax which is being transmitted by the sunlight. In order to understand what changes we can observe due to this, let us discuss the different possible outcomes given in the options.

Complete Step-by-Step Solution:
Sublimation: Sublimation occurs when a substance is converted from its solid state to its gaseous state without ever going through the liquid state. This usually happens when energy is provided to sublime solids and they readily convert to their gaseous states. Wax is not a sublime solid, hence does not undergo sublimation.
Melting: Melting occurs when a substance is converted from its solid state to its liquid state, when sufficient amount of energy is provided to the liquid. This trend is observed by regular solids and the temperature at which this conversion takes place is known as the melting temperature of the solid. Wax is regular solid and undergoes melting.
Condensation: Condensation occurs when a substance is converted from its gaseous state to its liquid state, when sufficient amount of energy is removed from the gas. The situation provided to us involves addition of energy and not its removal. Hence this is not the correct option.
Evaporation: Evaporation occurs when a substance is converted from its liquid state to its gaseous state, when sufficient amount of energy is provided to the liquid. The situation provided to us states that the piece of wax is placed in the sun. Before this experiment is done, the sample is at room temperature. And wax is in solid state at room temperature. So the situation of evaporation would not arise for the given experiment.

Hence, Option B is the correct option.

Note: When sunlight is provided, the energy from the sunlight is used to increase the kinetic energy of the molecules of the solid. Once the energy provided by the sunlight is sufficient enough, a change in the state of the solid would take place depending on the type of solid, i.e. melting or sublimation.