High School

An ice cube is placed in a microwave oven. Suppose the oven delivers 115 W of power to the ice cube and that it takes 32,200 J to melt it.

How long will it take to melt the ice cube completely?

Answer :

The time required for the microwave oven to melt the ice cube is approximately 279.13 seconds.

To find the time required, we first calculate the energy supplied by the microwave oven per second:

[tex]\[ \text{Power} = 115 \, \text{W} \][/tex]

Since power is the rate of energy transfer per unit time, the energy supplied per second is 115 J/s.

Next, we divide the total energy required to melt the ice cube (32200 J) by the energy supplied per second:

[tex]\[ \text{Time} = \frac{\text{Total Energy}}{\text{Energy per second}} \][/tex]

[tex]\[ \text{Time} = \frac{32200 \, \text{J}}{115 \, \text{J/s}} \][/tex]

[tex]\[ \text{Time} \approx 279.13 \, \text{seconds} \][/tex]

This calculation demonstrates that it would take approximately 279.13 seconds for the microwave oven to provide enough energy to melt the ice cube completely.

The process involves continuously supplying energy to the ice cube until it reaches its melting point, where the absorbed energy is used to break the intermolecular bonds and transition the ice into water. It's important to note that this calculation assumes ideal conditions and neglects factors like heat loss to the surroundings and variations in microwave efficiency, which could affect the actual time required for melting.