eZine · Nigerian exams
Quantity of heat
JAMB Physics topic guide with 2 practice questions.
What to revise
- heat as a form of energy
- heat capacity and specific heat capacity of solids and liquids
- determination of heat capacity and specific heat capacity by simple methods, e.g. method of mixtures, electrical method and Newton's law of cooling
You should be able to
- differentiate between heat capacity and specific heat capacity
- determine heat capacity and specific heat capacity using simple methods
- solve numerical problems
From JAMB's Physics syllabus official. Full syllabus →
eZine's published bank has 6 questions on this topic (counted 29 October 2026).
Practice questions
Question 1 · Quantity of heat
According to Newton's law of cooling, the rate of heat loss from a cup of hot tea in a draughty room is proportional to
Show answer and explanation
Answer: B. the excess of its temperature over that of the surroundings
Under forced convection, rate of loss of heat ∝ (θ − θ_surroundings). The fourth-power law is Stefan's law for radiation; mass affects the rate of temperature fall, not the law; no square law applies.
eZine practice question (original, teacher-reviewed)
Question 2 · Quantity of heat
How much heat is needed to raise the temperature of 2 kg of water from 25 °C to 75 °C? (specific heat capacity of water = 4200 J kg^-1 K^-1)
Show answer and explanation
Answer: A. 4.2 × 10^5 J
Q = mcΔθ = 2 × 4200 × (75 − 25) = 4.2 × 10^5 J. 2.1 × 10^5 J uses 1 kg; 6.3 × 10^5 J uses the final temperature 75 °C as Δθ; 8.4 × 10^3 J omits Δθ.
eZine practice question (original, teacher-reviewed)
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