Question

Identical amounts of heat are applied to 50 g blocks of lead, iron, and copper, all at an initial temperature of 25 °C. Which block will have the largest increase in temperature?

Answer 1

Answer:

Lead will have the largest increase in temperature.

Explanation:

Given:

The heat supplied to three equal mass blocks is same. The initial temperature of each block is 25 °C. The three blocks are of different material- iron, copper and lead.

The heat supplied to a body is directly proportional to its mass, specific heat capacity and the increase in temperature and is given as:

$Q=mc\Delta T\\Q\rightarrow Heat\\m\rightarrow mass\\c\rightarrow \textrm{Specif heat capacity}\\\Delta T\rightarrow \textrm{increase or decrease in temperature}$

Now, for the given question, for the three blocks, $Q\ and\ m$ are same. Thus, specific heat capacity is inversely proportional to change in temperature.

This means that the block that has the highest value of $c$ has the least increase in temperature, $\Delta T$ and the one that has the least value of $c$ has the largest increase in temperature.

Specific heat capacity of the three blocks are:

Lead: $c=0.128\ J/gK$

Copper: $c=0.386\ J/gK$

Iron: $c=0.450\ J/gK$

Thus, lead has the least value of $c$. So, it will have the largest increase in temperature.