Question

Specific heat capacity of lead is 120$JK{{g}^{-1}}{{K}^{-1}}$. When 7200J of heat is supplied to 5kg of lead, the rise in temperature is
(A) 8$^{0}C$
(B) 10$^{0}C$
(C) 12$^{0}C$
(D) 14$^{0}C$

Answer 1

Hint: Heat is a form of energy which gets transferred between the bodies having a temperature difference between them. If two bodies are in touch with each other than the heat flows from the hotter body to the colder body.

Complete step by step solution:
The specific heat capacity i.e. c is the heat capacity of a sample of a substance divided by the mass of the same sample. Or we can say that it is the amount of energy that should be heated to one unit mass of the substance in order to cause an increase of one unit in temperature.
Given in the question:
Specific heat capacity of lead = 120$JK{{g}^{-1}}{{K}^{-1}}$
Amount of heat supplied = 7200 J
Amount of lead = 5 Kg
We have to find the rise in temperature,
To solve this question we will use the formula
Specific heat i.e. Q = $ms\Delta T$
Where q is the amount of heat supplied, m is the mass of lead, s is the specific heat and delta t is the rise in temperature.
\[\Delta T=\dfrac{Q}{ms}=\dfrac{7200}{(5)(120)}\]
The change in temperature = 12$^{0}C$

Hence the correct answer is option (C) i.e. When 7200 J of heat is supplied to 5kg of lead, the rise in temperature is = 12$^{0}C$.

Note: Water has a high heat capacity; this is due to the property of water known as hydrogen bonding. Specific heat depends on the starting temperature and pressure and this can sometimes be ignored in practical applications. Specific heat is an intrinsic property of a substance.