Question 1

What is the specific heat capacity?

Accepted Answer

Specific heat capacity is defined as the heat energy needed to raise the temperature of 1 kg of a substance by 1°C, measured in J/(kg·°C).

Question 2

A metal rod is heated from 25°C to 75°C. What is the change in temperature in Kelvin?

Accepted Answer

Temperature change is the same in Kelvin and Celsius scales; ΔT = 75 - 25 = 50 K.

Question 3

Which of the following is the correct relationship between heat and temperature?

Accepted Answer

Heat is the form of energy transferred between objects due to temperature difference, whereas temperature measures the average kinetic energy of particles in a substance.

Question 4

At what temperature are the Celsius and Fahrenheit scales equal?

Accepted Answer

Using the formula C/5 = (F-32)/9, when C = F, we get C = -40.

Question 5

An object absorbs 5000 J of heat and its temperature rises from 20°C to 40°C. If the mass of the object is 2 kg, its specific heat capacity is:

Accepted Answer

Using Q = m × c × ΔT, we get c = Q/(m × ΔT) = 5000/(2 × 20) = 125 J/kg°C.

Question 6

The temperature at which the density of water is maximum is:

Accepted Answer

Water has its maximum density at 4°C, which is an anomalous property of water and important for aquatic life.

Question 7

If the temperature of a gas is increased from 27°C to 127°C at constant volume, the pressure will increase by a factor of:

Accepted Answer

Using Gay-Lussac's Law (P₁/T₁ = P₂/T₂), P₂/P₁ = 400K/300K = 1.33, which gives a ratio increase of 1.5 when properly calculated.

Question 8

A steel rod of length 1 m is heated from 0°C to 50°C. If the coefficient of linear expansion is 12 × 10⁻⁶ per °C, the increase in length will be approximately:

Accepted Answer

Using ΔL = L₀ × α × ΔT = 1 × 12 × 10⁻⁶ × 50 = 6 × 10⁻⁴ m = 0.6 mm.

Question 9

The specific heat capacity of a substance is defined as the amount of heat required to:

Accepted Answer

Specific heat capacity is the heat energy needed to raise the temperature of 1 kg of a substance by 1°C (or 1 K).

Question 10

The specific heat capacity of water is 4200 J/kg·K. If 2 kg of water is heated from 25°C to 75°C, how much heat energy is required?

Accepted Answer

Using Q = m × c × ΔT, where Q = 2 × 4200 × (75 - 25) = 2 × 4200 × 50 = 420,000 J.

Question 11

Two objects A and B are in thermal contact. Object A is at 50°C and object B is at 30°C. Heat flows from A to B until thermal equilibrium is reached. Which statement is correct?

Accepted Answer

Heat flows from higher to lower temperature regions; thermal equilibrium is achieved when both objects reach the same final temperature.

Question 12

A metal rod is heated from 20°C to 80°C. If the coefficient of linear expansion of the metal is 1.2 × 10⁻⁵ K⁻¹ and the original length is 2 m, what is the increase in length of the rod?

Accepted Answer

Using ΔL = L₀ × α × ΔT, where ΔT = 60 K, ΔL = 2 × 1.2 × 10⁻⁵ × 60 = 1.44 × 10⁻³ m.

Agniveer Army GD Heat & Temperature

Heat & Temperature — Practice Questions