Question

The temperature of a 3 kg block of aluminium increased by 3 degrees. How much heat would be needed to raise the temperature of a 9 kg block of aluminum by 3 degrees?

• A. 9 times as much heat as the 3 kg block
• B. 3 times as much heat as the 3 kg block
• C. the same amount of heat as the 3 kg block
• D. one-third as much heat as the 3 kg block
• E. one-ninth as much heat as the 3 kg block

Answer 1

The correct option is B 3 times as much heat as the 3 kg block

Given : $\Delta T=3^{o}C$

Let the specific heat of aluminium be $S$.

The initial mass to be heated $m_i=3kg$

$\therefore$ $Q_i=m_{i}S\Delta T=3\times S\times 3=9SJ$

Now the mass of aluminium to be heated $m_f=9kg$

$\therefore$ Heat required $Q_f=9\times S\times 3=27S=3Q_{i}J$

Thus option B is correct.