Consider the following assertions :1. The heat flows from a hotter ob...
- Heat Transfer: The movement of heat from a warmer object to a colder one – when two substances at different temperatures are mixed together, heat flows from the warmer body to the cooler body until they reach the same temperature (Zeroth Law of
- Thermodynamics – Thermal Equilibrium). Part of the heat lost by the warmer body is transferred to the cooler body and part is lost to the surrounding object or the air.
Convection is the process of heat transfer by the bulk movement of molecules within fluids such as gases and liquids. The initial heat transfer between the object and the fluid takes place through conduction, but the bulk heat transfer happens due to the motion of the fluid.
• Convection is the process of heat transfer in fluids by the actual motion of matter.
• It happens in liquids and gases.
• It may be natural or forced.
• It involves a bulk transfer of portions of the fluid. Conduction is the transfer of energy in the form of heat or electricity from one atom to another within an object by direct contact. Conduction occurs in solids, liquids, and gases. However, solids transfer energy most efficiently since the molecules in solids are most tightly packed, and the molecules are closer together, as shown in this figure. For liquids and gases, the density of the particles are generally lower than those of solids and the particles are farther apart, so the energy transfer is less efficient.
Consider the following assertions :1. The heat flows from a hotter ob...
Explanation:
Assertion 1: The heat flows from a hotter object to a colder object.
This assertion is correct. According to the second law of thermodynamics, heat naturally flows from a region of higher temperature to a region of lower temperature. This is because objects tend to reach thermal equilibrium, where the temperatures of two objects become equal. Therefore, heat transfer occurs until the temperatures of both objects are the same.
Assertion 2: The mode of heat transfer that continues till the whole water gets heated is known as convection.
This assertion is incorrect. The mode of heat transfer that continues until the whole water gets heated is actually conduction, not convection. In conduction, heat is transferred through direct contact between particles or objects. When a substance is heated, the particles gain energy and start vibrating, transferring this energy to neighboring particles. This process continues until the entire substance is heated.
Assertion 3: The process by which heat is transferred from the hotter end to the colder end of an object is known as conduction.
This assertion is correct. Conduction is the process by which heat is transferred through a solid or between solids that are in direct contact with each other. In this process, heat energy is transferred from the hotter end to the colder end of the object. The particles in the hotter region have higher kinetic energy and transfer this energy to neighboring particles with lower kinetic energy, causing them to vibrate and increase their temperature.
Conclusion:
From the given assertions, it can be concluded that Assertion 1, Assertion 2, and Assertion 3 are all correct. Heat flows from a hotter object to a colder object, the mode of heat transfer that continues until the whole water gets heated is conduction, and the process by which heat is transferred from the hotter end to the colder end of an object is also conduction. Therefore, the correct answer is option 'D' - all three assertions are correct.
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