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.
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.
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.
The correct answer is option A. When the solid metal ball is heated, the particles within it gain kinetic energy, causing them to vibrate more vigorously. This increased vibration leads to expansion throughout the metal, including the cavity inside. As the metal expands, the volume of the cavity incRead more
The correct answer is option A. When the solid metal ball is heated, the particles within it gain kinetic energy, causing them to vibrate more vigorously. This increased vibration leads to expansion throughout the metal, including the cavity inside. As the metal expands, the volume of the cavity increases, resulting in option A: an increase in volume. This phenomenon is due to the thermal expansion properties of the metal, which causes it to expand uniformly in all directions when heated. Therefore, heating the metal ball will cause the volume of the cavity inside it to increase, as the metal expands to accommodate the higher temperature, resulting in a larger volume for the cavity.
The correct answer is; option A. When a glass rod is kept in steam, its length increases due to thermal expansion. However, the width of the glass rod remains unaffected. This phenomenon occurs because glass primarily expands in one direction when subjected to heat, which is along its length. The moRead more
The correct answer is; option A. When a glass rod is kept in steam, its length increases due to thermal expansion. However, the width of the glass rod remains unaffected. This phenomenon occurs because glass primarily expands in one direction when subjected to heat, which is along its length. The molecular structure of glass allows for expansion in the direction of the applied heat while maintaining relatively unchanged dimensions perpendicular to that direction. Therefore, although the glass rod elongates when exposed to steam, its width does not experience significant alteration. Option B is incorrect as the width doesn’t decrease. Option C is incorrect as the width doesn’t increase. Option D is irrelevant as the question pertains to physical changes rather than structural disorganization. Thus, the correct choice is option A, where the width of the glass rod remains unaffected by exposure to steam.
The 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.
See lessA solid metal ball has a cavity inside it. When this metal ball is heated, the volume of the cavity will
The correct answer is option A. When the solid metal ball is heated, the particles within it gain kinetic energy, causing them to vibrate more vigorously. This increased vibration leads to expansion throughout the metal, including the cavity inside. As the metal expands, the volume of the cavity incRead more
The correct answer is option A. When the solid metal ball is heated, the particles within it gain kinetic energy, causing them to vibrate more vigorously. This increased vibration leads to expansion throughout the metal, including the cavity inside. As the metal expands, the volume of the cavity increases, resulting in option A: an increase in volume. This phenomenon is due to the thermal expansion properties of the metal, which causes it to expand uniformly in all directions when heated. Therefore, heating the metal ball will cause the volume of the cavity inside it to increase, as the metal expands to accommodate the higher temperature, resulting in a larger volume for the cavity.
See lessWhen a glass rod is kept in steam, its length increases but its width
The correct answer is; option A. When a glass rod is kept in steam, its length increases due to thermal expansion. However, the width of the glass rod remains unaffected. This phenomenon occurs because glass primarily expands in one direction when subjected to heat, which is along its length. The moRead more
The correct answer is; option A. When a glass rod is kept in steam, its length increases due to thermal expansion. However, the width of the glass rod remains unaffected. This phenomenon occurs because glass primarily expands in one direction when subjected to heat, which is along its length. The molecular structure of glass allows for expansion in the direction of the applied heat while maintaining relatively unchanged dimensions perpendicular to that direction. Therefore, although the glass rod elongates when exposed to steam, its width does not experience significant alteration. Option B is incorrect as the width doesn’t decrease. Option C is incorrect as the width doesn’t increase. Option D is irrelevant as the question pertains to physical changes rather than structural disorganization. Thus, the correct choice is option A, where the width of the glass rod remains unaffected by exposure to steam.
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