Question

The temperature of a block of iron increases by 2 K when 3760 J of heat are added to it. What is the mass of the block of iron? The specific heat capacity of iron is 470J/kg*K.


5 kg

4 kg

2 kg

3 kg

Answer 1

The amount of heat needed to increase the temperature of a substance by $\Delta T$ is:
$Q=m C_s \Delta T$
where
Q is the amount of heat
m is the mass of the substance
Cs is the specific heat capacity of the substance
$\Delta T$ is the variation of temperature

We know the heat added to the block of iron, Q=3760 J, its variation of temperature, $\Delta T=2 K$, and the specific heat capacity of iron, $C_s = 470 J/(kg K)$, so we can re-arrange the previous formula to find the mass of the block:
$m= \frac{Q}{C_s \Delta T}= \frac{3760 J}{(470 J/(kgK))(2 K)}=4 kg$