Thermal Energy Transfer Quiz! Trivia

In the given question, it is stated that the hot water in the black can cools more quickly than the hot water in the white can. This can be explained by the fact that black absorbs more heat and radiates it faster than white. Similarly, it is also mentioned that the cold water in the black can heats up more quickly than the cold water in the white can. This can be attributed to the fact that black also absorbs heat faster than white. Therefore, the correct row that shows the reasons for this is A.

Black surfaces absorb radiation well because they have a high absorption coefficient for electromagnetic radiation. When sunlight hits a black surface, it is absorbed rather than reflected, causing the surface to heat up. This is why the tubes inside solar heating panels are painted black, as it allows them to efficiently absorb the Sun's radiation and transfer that heat to the water inside the tubes.

Black surfaces absorb and emit more energy compared to white surfaces. Therefore, the matt black metal plate will absorb more energy from the radiant heater and also emit more energy than the matt white metal plate in the given time period. This is due to the higher emissivity and absorptivity of black surfaces, making them more efficient at both absorbing and radiating heat.

Heat transfer through a vacuum takes place by radiation only. Unlike conduction and convection, which require a medium like solids, liquids, or gases to transfer heat, radiation can occur in a vacuum. This is because radiation is the transfer of heat energy through electromagnetic waves, which can travel through empty space. Therefore, when there is no medium present, such as in a vacuum, heat transfer can only occur through radiation.

Heat is conducted in a metal through the vibration of atoms and the movement of electrons. The atoms in the metal vibrate due to the input of heat energy, transferring this energy to neighboring atoms through collisions. At the same time, the free electrons in the metal are able to move freely and carry thermal energy with them. This combination of atomic vibrations and electron movements allows heat to be conducted efficiently in a metal.

Without the specific information about the colors and textures of the cans, it is difficult to determine the exact reason why can A cools the most rapidly. However, it is possible that can A has a lighter color and a smoother texture compared to the other cans. Lighter colors tend to reflect more heat, while smoother textures allow for better heat conduction. These factors could contribute to can A cooling more rapidly than the others.

In a vacuum flask, the vacuum prevents both conduction and convection. Conduction is the transfer of heat through direct contact between two objects, and since the vacuum flask has a vacuum between its inner and outer layers, there is no material or medium for heat to conduct through. Convection, on the other hand, is the transfer of heat through the movement of a fluid or gas. Again, since there is no fluid or gas present in the vacuum, convection is also prevented. However, radiation, which is the transfer of heat through electromagnetic waves, is not prevented by the vacuum and can still occur in a vacuum flask.

Can A contains the coolest water because it is painted dull black, which is a better absorber of heat compared to polished silver. The dull black surface absorbs more heat from the surroundings, causing the water inside the can to lose heat faster and cool down more quickly. On the other hand, the polished silver surface reflects more heat away, resulting in slower heat loss and warmer water inside the can.

When a refrigerator is switched on for the first time, the air surrounding the ice-box is cooled. As the air cools down, its density increases. This is because cooling causes the air molecules to slow down and come closer together, resulting in a higher density. In terms of its position inside the refrigerator, the cooled air tends to sink down towards the bottom of the refrigerator. This is because cold air is denser than warm air, so it displaces the warmer air and sinks to the lower areas of the refrigerator. Therefore, the density of the air increases and its position inside the refrigerator is lower.

The correct answer is 1.0 cm because the total thermal energy transfer is least. This is because the graph shows that as the thickness of the layer of air increases, the amount of thermal energy transfer also increases. However, after reaching a certain point, the increase in thickness does not significantly affect the energy transfer. Therefore, the thickness of 1.0 cm produces the smallest energy transfer as it is the point where the increase in energy transfer starts to level off.

Convection is the method of thermal energy transfer that is primarily caused by density changes. When a fluid, such as air or water, is heated, it becomes less dense and rises, while the cooler, denser fluid sinks. This movement of fluids transfers heat energy from one place to another. Therefore, the correct answer is convection only.

The main process by which the heat is transferred through the radiator and then spread around the room is conduction. In conduction, heat is transferred through direct contact between objects or substances. In this case, the hot water in the metal radiator transfers heat to the metal through conduction. The metal, being a good conductor of heat, then spreads the heat to the surrounding air molecules in the room. This process continues until the heat is evenly distributed throughout the room.

Water is a poor conductor of heat, which means it does not easily transfer heat from one part to another. When the water at the top of the tank is heated, it does not efficiently transfer the heat to the water at the bottom of the tank. Therefore, the water at the bottom stays cold for some time.

Painting surface S silver reduces heat losses by radiation. Silver is a good reflector of heat and light, so it reflects the radiation back into the vessel, preventing it from escaping. This helps to maintain the temperature of the hot liquid inside the vessel. In contrast, painting surface Q black would absorb heat and increase heat losses, while painting surface R black would not reflect much heat and also increase heat losses. A vacuum in the space between the walls would reduce heat losses by conduction and convection, but not by radiation.

Heat is transferred through the aluminium pan through a process called conduction. Conduction occurs when heat energy is transferred from one particle to another through direct contact. The aluminium pan, being a good conductor of heat, allows the heat to move from the stove to the water efficiently. On the other hand, heat is transferred through the plastic handle through a process called convection. Convection occurs when heat energy is transferred through the movement of a fluid, in this case, air. The heat from the pan warms up the air surrounding the handle, and this warm air then transfers the heat to the handle.

The surface of the cup is extremely hot because convection takes place in the boiling water. Convection is the transfer of heat through the movement of a fluid, in this case, the boiling water. As the water boils, hot water rises to the surface and cooler water sinks to the bottom. This creates a continuous circulation of hot water, transferring heat to the cup's surface and making it hot to the touch. Additionally, silver is a good conductor of heat, which further enhances the transfer of heat from the boiling water to the cup's surface.