Question

$2000J$ of energy is needed to heat $1kg$ of paraffin through $1^{o}C$ . How much energy is needed to heat $10kg$ of paraffin through $2^{o}C$ ?

• A. $4000J$
• B. $10,000J$
• C. $20,000J$
• D. $40,000J$

Answer 1

The correct option is D $40,000J$

The heat energy required to raise the temperature of unit mass of substance through unit degree is called specific heat of substance . As given $2000J$ energy is needed to heat $1kg$ of paraffin through $1^{o}C$, therefore specific heat of paraffin will be $2000J/kg{-}^{o}C$.

Now, heat energy required to raise the temperature of mass $m$ of substance (specific heat $c$) through $\Delta t$ is given by ,

$Q=mc\Delta t$,

Given: $m=10kg,\Delta t=2^{o}C,c=2000J/kg{-}^{o}C$

$Q=10\times 2000\times 2=40,000J$