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Sun’s heat comes to the Earth through which of the following types of communication medium?
The correct answer is [B] Radiation. The Sun's heat reaches the Earth primarily through radiation. Radiation is the transfer of heat energy through electromagnetic waves, such as light and infrared radiation, that travel through the vacuum of space. These electromagnetic waves carry energy from theRead more
The correct answer is [B] Radiation. The Sun’s heat reaches the Earth primarily through radiation. Radiation is the transfer of heat energy through electromagnetic waves, such as light and infrared radiation, that travel through the vacuum of space. These electromagnetic waves carry energy from the Sun and warm the Earth’s surface when they are absorbed. Unlike convection, which involves the transfer of heat through the movement of fluids, and condensation, which is a phase change process, radiation does not require a medium to propagate. Heat exchange is a broad term that can encompass various methods of transferring heat, including conduction, convection, and radiation, but it is not specific to the transmission of heat from the Sun to the Earth.
See lessWhat are the two main purposes of cattle husbandry?
The two main purposes of cattle husbandry are to produce milk and dairy products for human consumption and to provide draft power for agricultural activities, contributing to both food production and farming efficiency.
The two main purposes of cattle husbandry are to produce milk and dairy products for human consumption and to provide draft power for agricultural activities, contributing to both food production and farming efficiency.
See lessWater in an electric kettle gets heated due to
The correct answer is [A] Due to conduction. Water in an electric kettle gets heated primarily due to conduction. When the heating element of the kettle comes into direct contact with the water, thermal energy is transferred through the metal of the element to the water molecules, causing them to viRead more
The correct answer is [A] Due to conduction. Water in an electric kettle gets heated primarily due to conduction. When the heating element of the kettle comes into direct contact with the water, thermal energy is transferred through the metal of the element to the water molecules, causing them to vibrate and increase in temperature. This process is a classic example of conduction, where heat is transmitted through direct contact between particles. While convection may play a minor role as the heated water rises and cooler water sinks, and radiation may contribute slightly to the overall heating process, the main mechanism responsible for heating the water in an electric kettle is conduction.
See lessHeat is transferred in liquids and gases by which of the following methods?
Heat is primarily transferred in liquids and gases by the method of convection. Convection involves the actual movement of fluid particles, carrying heat with them as they circulate. When a fluid is heated, its particles become less dense and rise, while cooler, denser particles sink. This creates aRead more
Heat is primarily transferred in liquids and gases by the method of convection. Convection involves the actual movement of fluid particles, carrying heat with them as they circulate. When a fluid is heated, its particles become less dense and rise, while cooler, denser particles sink. This creates a continuous circulation of the fluid, transferring heat throughout. While conduction can also occur within fluids, it is less efficient compared to convection due to the fluid’s ability to flow. Radiation can also transfer heat in liquids and gases, but it does so primarily in the form of infrared radiation, which is less significant compared to convection. Therefore, while all three methods—conduction, convection, and radiation—can transfer heat in liquids and gases to some extent, convection is the dominant mechanism in this context. The correct answer is [B] Convection.
See lessIn which method of transmission of heat, particles of matter do not move on their own from one place to another?
In the method of transmission of heat known as conduction, particles of matter do not move on their own from one place to another. Conduction involves the transfer of heat through direct contact between particles in a material. When one part of a solid object is heated, the particles in that regionRead more
In the method of transmission of heat known as conduction, particles of matter do not move on their own from one place to another. Conduction involves the transfer of heat through direct contact between particles in a material. When one part of a solid object is heated, the particles in that region vibrate more vigorously. These vibrations are passed along to neighboring particles, transferring energy from the hotter region to the cooler region. However, the particles themselves do not move significantly from their positions; rather, it is the energy that is transmitted through the material.
In contrast, convection involves the actual movement of fluid particles (liquids or gases) from one place to another, carrying heat with them. Radiation does not require any medium and involves the transfer of heat through electromagnetic waves.
Therefore, the correct answer is [A] Conduction, as it is the method where particles do not move on their own from one place to another.
See lessThe method of transmission of heat is
The method of transmission of heat includes conduction, convection, and radiation, covering all the given options. Conduction is the transfer of heat through direct contact between molecules, typically occurring in solids. An example is a metal rod heating up when one end is placed in a flame. ConveRead more
The method of transmission of heat includes conduction, convection, and radiation, covering all the given options. Conduction is the transfer of heat through direct contact between molecules, typically occurring in solids. An example is a metal rod heating up when one end is placed in a flame. Convection is the transfer of heat through the movement of fluids, such as liquids and gases. This process can be observed when warm air rises and cool air descends, creating convection currents. Radiation is the transfer of heat through electromagnetic waves, which can occur even through a vacuum. The heat we feel from the sun is due to radiation. Each of these methods operates under different principles and in different mediums, but together, they encompass all the ways heat can be transmitted. Therefore, the correct answer is [D] All of the above.
See lessWhen water freezes due to cold in winter, fishes and other aquatic organisms can
When water freezes due to cold in winter, fishes and other aquatic organisms can survive because only the upper layer of water freezes. This phenomenon occurs because ice is less dense than liquid water, causing it to float on the surface. The layer of ice acts as an insulating barrier, maintainingRead more
When water freezes due to cold in winter, fishes and other aquatic organisms can survive because only the upper layer of water freezes. This phenomenon occurs because ice is less dense than liquid water, causing it to float on the surface. The layer of ice acts as an insulating barrier, maintaining a relatively stable and warmer temperature in the water below, typically around 4°C. This insulated environment allows fish and other aquatic organisms to survive the winter. Additionally, many aquatic species have adapted to cold conditions, slowing their metabolism and becoming less active to conserve energy. This adaptation helps them survive in the lower, unfrozen layers of the lake. Therefore, the correct answer is [A] survive, because only the upper layer of water freezes.
See lessThe water on the surface of a lake is just about to freeze. What will be the temperature of water at the bottom of the lake?
When the water on the surface of a lake is just about to freeze, the temperature of the water at the bottom of the lake will be approximately 4°C. This is due to the unique property of water where it reaches its maximum density at 4°C. As the surface water cools down to 0°C and begins to freeze, itRead more
When the water on the surface of a lake is just about to freeze, the temperature of the water at the bottom of the lake will be approximately 4°C. This is due to the unique property of water where it reaches its maximum density at 4°C. As the surface water cools down to 0°C and begins to freeze, it becomes less dense and remains on top, while the denser water at 4°C sinks to the bottom. This process ensures that the bottom of the lake remains at a relatively constant temperature of 4°C, providing a stable environment for aquatic life during winter. The layering effect, known as thermal stratification, prevents the entire lake from freezing solid, thus preserving the ecosystem within. Therefore, the correct answer is [D] 4° C.
See lessWhy is a small space left at the joint between two railway tracks?
The correct answer is [B]. A small space is left at the joint between two railway tracks to accommodate the expansion and contraction of the metal due to temperature changes. This phenomenon is known as thermal expansion. Metals, including steel used in railway tracks, expand when heated and contracRead more
The correct answer is [B]. A small space is left at the joint between two railway tracks to accommodate the expansion and contraction of the metal due to temperature changes. This phenomenon is known as thermal expansion. Metals, including steel used in railway tracks, expand when heated and contract when cooled. If no space is provided, the tracks would buckle and deform during hot weather as the metal expands. Conversely, in cold weather, the lack of space could cause the tracks to contract and create gaps that might lead to derailments. Therefore, these gaps are crucial for maintaining the structural integrity and safety of the railway system. This precautionary measure is essential for the reliable and safe operation of trains, preventing potential accidents and ensuring smooth travel. The correct answer is [B] Because the metal expands when heated and contracts when cooled.
See lessWhen a bottle is filled with water and allowed to freeze, then the bottle breaks, because
The correct answer is option A. When water freezes, it expands as it forms ice crystals, exerting pressure on the walls of the bottle. This expansion exceeds the tensile strength of the bottle material, causing it to rupture. Option B is incorrect because the bottle doesn't shrink at freezing point;Read more
The correct answer is option A. When water freezes, it expands as it forms ice crystals, exerting pressure on the walls of the bottle. This expansion exceeds the tensile strength of the bottle material, causing it to rupture. Option B is incorrect because the bottle doesn’t shrink at freezing point; rather, it remains the same size. Option C is irrelevant to the mechanism of bottle breakage due to freezing. Option D is incorrect because water expands when it freezes, not when heated. Therefore, the expansion of water upon freezing, rather than any external factors or properties of the bottle, is the primary reason for the bottle breaking when filled with water and allowed to freeze.
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