Grab 4 marks/ specific heat capacity/SEE Important question explained By: Subash sir/Ninja Technique

These questions generally require a deeper understanding and application of the core concept, often involving calculations and explanations.

Important Specific Heat Capacity Questions for 4 Marks
The key questions for 4 marks typically fall into the following categories:

1. Calculation-Based Problems (Numericals)
These questions involve applying the specific heat capacity formula and often combine it with other thermal concepts.

Heat Energy Calculation: Calculate the heat energy (Q) gained or lost by a substance of a given mass (m) when its temperature changes (ΔT), using the specific heat capacity (c).

Formula: Q=mcΔT

Example: Calculate the heat required to raise the temperature of 2 kg of water from 20
∘
C to 80
∘
C, given that the specific heat capacity of water is 4200 J/kg
∘
C.

Method of Mixtures (Calorimetry): These are common 4-mark questions where two different substances (e.g., hot metal and cold water) at different temperatures are mixed.

Principle: Heat lost by the hot body = Heat gained by the cold body.

Example: A piece of metal of a certain mass and temperature is dropped into a known mass of water at a lower temperature. Calculate the final equilibrium temperature or the specific heat capacity of the metal. Assumptions like "no heat loss to the surroundings" must be stated.

Latent Heat Combination: Questions that involve both specific heat capacity and specific latent heat (fusion or vaporization).

Example: Calculate the total heat energy required to convert a given mass of ice at a certain temperature (e.g., −10
∘
C) into water at a higher temperature (e.g., 50
∘
C). This requires three separate calculations: heating the ice, melting the ice, and heating the water.

2. Conceptual/Reasoning Questions (Give Reasons)
These questions test the understanding of the practical implications of specific heat capacity. For a 4-mark question, a minimum of four distinct, well-explained points are typically expected.

High Specific Heat Capacity of Water: Explain the advantages of the high specific heat capacity of water in applications such as:

Cooling agent in car radiators.

Hot water bags (providing warmth for a longer time).

Moderating weather in coastal areas.

Providing stable aquatic habitats.

Low Specific Heat Capacity of Metals: Explain why substances with low specific heat capacity (like metals) are suitable for:

Making cooking utensils (they heat up quickly).

Making the base of an electric iron (they store less heat, transferring it quickly).

Rate of Heating/Cooling Comparison: Explain why two substances of the same mass, when given the same amount of heat, show different temperature increases (or why they cool down at different rates). The explanation must link the energy received to the specific heat capacity and the resulting change in temperature (ΔT).

3. Experimental Procedure Questions
Describe the experimental setup and procedure used to determine the specific heat capacity of a given substance, often a solid or a liquid.

Key steps: Insulation, measuring mass and initial temperature, applying known heat energy (e.g., using an electric heater and joulemeter or ammeter/voltmeter/timer), measuring final temperature, and using the formula to calculate the specific heat capacity. The expected response for 4 marks includes a neat diagram, procedure, and formula.

The video below offers an example of how specific heat capacity questions are worked out, which is relevant for the numerical questions expected in your exam.