Chapter U5.5, Problem 5E

Interpretation Introduction

Interpretation:

The reason due to which metal keys become hotter than plastic pair of sunglasses when left in the sun needs to be explained.

Concept Introduction :

The specific heat capacity is the amount of energy that should be added to one unit of mass of the substance in order to increase the temperature by one unit.

Answer to Problem 5E

The metal have a lesser heat capacity than the plastic.

Explanation of Solution

The amount of heat required for temperature change can be calculated as follows:

  $q=mc\Delta T$

So, it directly depends on the specific heat capacity of the substance.

The keys and the sunglasses absorb the equal amount of energy; the temperature of the metal keys raises more because the metal must have a lesser heat capacity than the plastic.