Question

Q1.A 500
1.95 kJ of heat is required to raise the temperature of 500 g of lead from 15°C to its final temperature. Taking the
specific heat capacity of lead to be 130 J/kg -C), the final temperature is:
A 45 C
B. 37.5
C
C. 30°C
D. 22.5 C
Work in thermodynamics depends upon:
n None of them​

Answer 1

Explanation:

Answer:

Formula to calculate Heat energy is given by:

${\boxed{Q = m.s.\Delta T}$

Here, 'Q' refers to the heat energy, 'm' refers to the mass of the body being heated, 's' refers to the specific heat capacity and ΔT refers to the change in temperature.

According to the question,

→ Q = 1.95 kJ = 1.95 × 10³ kJ = 1950 J

→ m = 500g = 0.5 kg

→ s = 130 J/kg.°C

→ ΔT = ( T - 15°C ) [T = Final temperature]

Substituting the values we get:

→ 1950 J = 0.5 kg × 130 J/kg.°C × ( T - 15°C )

→ 1950 J = 65 J/°C × ( T - 15°C )

→ ( 1950/65 ) °C = ( T - 15°C )

→ 30°C = T - 15°C

→ T = 30°C + 15°C

→ T = 45°C

Hence Option (A) is the correct answer.