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32 public questions tagged with this topic.

Specific Heat Capacity and Latent Heat

How much heat is required to convert 1 g of water from liquid at 100^circ C to vapor at 100^circ C at 1 atm ? (Latent he

**Latent heat** energy needed for phase change without temperature change, overcomes intermolecular forces, e.g., heating ice at 0°C to water at 0°C requires 334 kJ/kg, then heating water to 100°C requires c ΔT, then vaporization 2260 kJ/kg, illustrating two types of heat. Heat: Δ Q = m L . m = 1 g , L = 2256 J/g . Δ Q = 1 × 2256 = 2256 J . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal W = n R T ln(V₂/V₁), adiabatic P V^γ = const and η = 1 - T_c/T_h,

Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat

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Specific Heat Capacity and Latent Heat

What is the molar specific heat capacity at constant pressure for a monatomic gas if C_v = 12.45 J mol⁻¹ K⁻¹ and R = 8.3

**Specific heat capacity** c = Q/(m ΔT) (J/kg·K), molar C = Q/(n ΔT), heat required to raise temperature, Q = m c ΔT, for water c=4186 J/kg·K, latent heat L = Q/m for phase change at constant temperature, fusion L_f and vaporization L_v, Q = m L, e.g., ice melting L_f=3.34×10⁵ J/kg, water vaporization 2.26×10⁶ J/kg. C_p - C_v = R . C_p = C_v + R = 12.45 + 8.3 = 20.75 J mol⁻¹ K⁻¹ . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal W = n R T ln(V₂/V₁), adiabatic P V^γ

Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat

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Specific Heat Capacity and Latent Heat

A gas undergoes an adiabatic expansion from 10 L to 40 L , reducing its pressure from 8 atm to 1 atm . What is the value

**Heat capacity** at constant pressure C_p and volume C_v, C_p = C_v + R per mole, for solids Dulong-Petit C_v≈3R≈25 J/mol·K. Specific heat and latent heat govern temperature changes and phase transitions, Q = m c ΔT for heating, Q = m L for melting/boiling at constant T. For adiabatic: P₁ V₁^γ = P₂ V₂^γ . 8 × 10^γ = 1 × 40^γ . 8 = ((40)/(10))^γ ⇒ 8 = 4^γ . 4^γ = 2³ ⇒ 2²γ = 2³ ⇒ 2γ = 3 ⇒ γ = 1.5 . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P

Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat

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Temperature Scales and Triple Point

How much heat is required to raise 0.8kg of aluminium from 25∘C to 75∘C if its specific heat capacity is 900J kg−1K−1?

Given: m = 0.8kg, ΔT = 75−25 = 50∘C, s = 900Jkg−1K−1. Q = msΔT = 0.8×900×50 = 36000J = 36kJ. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 36 kJ. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.

Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.

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Temperature Scales and Triple Point

During the melting of ice at 0∘C, why does the temperature remain constant despite heat being supplied?

The heat supplied during melting (latent heat of fusion) is used to change the state from solid to liquid, overcoming intermolecular forces, not to increase temperature (Section 10.8). As per NCERT, applying relevant law/formula with correct units and sign convention leads to Heat is used to change the state, not raise temperature. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.

Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.

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Fluid Pressure, Pascal's Law and Manometers

Which of the following correctly relates the coefficients of linear and area expansion?

The coefficient of area expansion is approximately twice the coefficient of linear expansion (ΔA/A≈2αlΔT), as area involves two dimensions. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Area coefficient is twice the linear coefficient. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: University Physics, Chapter 17: Thermal Expansion.

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