Water boils when its vapor pressure equals the atmospheric pressure. At sea level, where the atmospheric pressure is approximately 1 atmosphere (101.3 kPa), this occurs at 100°C (212°F). However, the boiling point of water changes with altitude and atmospheric pressure. At higher altitudes, where atRead more
Water boils when its vapor pressure equals the atmospheric pressure. At sea level, where the atmospheric pressure is approximately 1 atmosphere (101.3 kPa), this occurs at 100°C (212°F). However, the boiling point of water changes with altitude and atmospheric pressure. At higher altitudes, where atmospheric pressure is lower, water boils at a lower temperature. Conversely, in a high-pressure environment, water boils at a higher temperature.
Among the given options:
– [A] “When its vapor pressure is one gram per square centimeter” is incorrect because boiling is not related to this specific pressure unit.
– [B] “When its vapor pressure is equal to 76 cm of mercury” is incorrect as this is specific to standard atmospheric pressure but doesn’t cover all conditions.
– [C] “Static vapor pressure of water is equal to atmospheric pressure” is correct.
– [D] “When the temperature of water reaches 100°C” is true only at sea level.
The process of a substance changing into vapor before its boiling point is known as evaporation. Evaporation occurs at the surface of a liquid when molecules with sufficient kinetic energy escape into the gaseous phase. Unlike boiling, which happens throughout the liquid at a specific temperature (tRead more
The process of a substance changing into vapor before its boiling point is known as evaporation. Evaporation occurs at the surface of a liquid when molecules with sufficient kinetic energy escape into the gaseous phase. Unlike boiling, which happens throughout the liquid at a specific temperature (the boiling point), evaporation can occur at any temperature below the boiling point. This process is influenced by factors such as temperature, surface area, humidity, and air movement. For example, water in a puddle evaporates even at room temperature, gradually turning into water vapor. Evaporation is a crucial part of the water cycle, contributing to processes like cooling, weather patterns, and drying of clothes. Therefore, the correct answer is [A] Evaporation. Understanding evaporation helps explain everyday phenomena and is fundamental in various scientific and industrial applications.
Rice cooks quickly in a pressure cooker because high pressure increases the boiling point of water. Under normal atmospheric pressure, water boils at 100°C. However, in a pressure cooker, the sealed environment raises the pressure, which in turn raises the boiling point of water to higher than 100°CRead more
Rice cooks quickly in a pressure cooker because high pressure increases the boiling point of water. Under normal atmospheric pressure, water boils at 100°C. However, in a pressure cooker, the sealed environment raises the pressure, which in turn raises the boiling point of water to higher than 100°C. This allows the water and steam inside the cooker to reach higher temperatures, which accelerates the cooking process. The higher temperature results in faster heat transfer to the rice, softening it more quickly than it would at the normal boiling point. This principle is why pressure cookers are efficient for cooking not only rice but also other foods that benefit from being cooked at higher temperatures and in shorter times. Therefore, the correct answer is [B] High pressure increases the boiling point of water. This understanding is essential for efficient cooking and energy conservation in culinary practices.
Man feels discomfort due to humidity primarily because sweat does not evaporate efficiently in high humidity conditions. Evaporation of sweat from the skin surface is a critical mechanism for cooling the body. In high humidity, the air is already saturated with moisture, significantly slowing down tRead more
Man feels discomfort due to humidity primarily because sweat does not evaporate efficiently in high humidity conditions. Evaporation of sweat from the skin surface is a critical mechanism for cooling the body. In high humidity, the air is already saturated with moisture, significantly slowing down the rate of sweat evaporation. As a result, the body retains more heat, leading to overheating and discomfort. This lack of effective cooling makes the body feel hotter and more uncomfortable compared to dry conditions, where sweat evaporates more readily and provides a cooling effect. Therefore, the correct answer is [C] Sweat not evaporating due to humidity. Understanding this phenomenon is essential for managing heat stress and designing cooling strategies in hot, humid environments, impacting areas such as workplace safety, athletic performance, and general well-being.
When a piece of ice floating in a glass of water completely melts, the level of water in the glass remains unchanged. This phenomenon can be explained by the principle of buoyancy and the displacement of water. A floating ice cube displaces a volume of water equal to the weight of the ice. When theRead more
When a piece of ice floating in a glass of water completely melts, the level of water in the glass remains unchanged. This phenomenon can be explained by the principle of buoyancy and the displacement of water. A floating ice cube displaces a volume of water equal to the weight of the ice. When the ice melts, it turns into water and occupies the same volume that was initially displaced. Since the density of ice is less than that of water, the melted ice, now in liquid form, fills the exact volume it previously displaced. Therefore, the overall water level in the glass does not change. This principle holds true for any ice floating in a liquid, assuming no additional factors such as temperature changes significantly affecting the water’s volume. Hence, the correct answer is [C] remain unchanged. Understanding this concept illustrates fundamental principles of physics and fluid dynamics.
When does water boil?
Water boils when its vapor pressure equals the atmospheric pressure. At sea level, where the atmospheric pressure is approximately 1 atmosphere (101.3 kPa), this occurs at 100°C (212°F). However, the boiling point of water changes with altitude and atmospheric pressure. At higher altitudes, where atRead more
Water boils when its vapor pressure equals the atmospheric pressure. At sea level, where the atmospheric pressure is approximately 1 atmosphere (101.3 kPa), this occurs at 100°C (212°F). However, the boiling point of water changes with altitude and atmospheric pressure. At higher altitudes, where atmospheric pressure is lower, water boils at a lower temperature. Conversely, in a high-pressure environment, water boils at a higher temperature.
Among the given options:
– [A] “When its vapor pressure is one gram per square centimeter” is incorrect because boiling is not related to this specific pressure unit.
– [B] “When its vapor pressure is equal to 76 cm of mercury” is incorrect as this is specific to standard atmospheric pressure but doesn’t cover all conditions.
– [C] “Static vapor pressure of water is equal to atmospheric pressure” is correct.
– [D] “When the temperature of water reaches 100°C” is true only at sea level.
Thus, the correct answer is [C].
See lessWhat is the process of a substance changing into vapor before its boiling point called
The process of a substance changing into vapor before its boiling point is known as evaporation. Evaporation occurs at the surface of a liquid when molecules with sufficient kinetic energy escape into the gaseous phase. Unlike boiling, which happens throughout the liquid at a specific temperature (tRead more
The process of a substance changing into vapor before its boiling point is known as evaporation. Evaporation occurs at the surface of a liquid when molecules with sufficient kinetic energy escape into the gaseous phase. Unlike boiling, which happens throughout the liquid at a specific temperature (the boiling point), evaporation can occur at any temperature below the boiling point. This process is influenced by factors such as temperature, surface area, humidity, and air movement. For example, water in a puddle evaporates even at room temperature, gradually turning into water vapor. Evaporation is a crucial part of the water cycle, contributing to processes like cooling, weather patterns, and drying of clothes. Therefore, the correct answer is [A] Evaporation. Understanding evaporation helps explain everyday phenomena and is fundamental in various scientific and industrial applications.
See lessRice cooks quickly in a pressure cooker because
Rice cooks quickly in a pressure cooker because high pressure increases the boiling point of water. Under normal atmospheric pressure, water boils at 100°C. However, in a pressure cooker, the sealed environment raises the pressure, which in turn raises the boiling point of water to higher than 100°CRead more
Rice cooks quickly in a pressure cooker because high pressure increases the boiling point of water. Under normal atmospheric pressure, water boils at 100°C. However, in a pressure cooker, the sealed environment raises the pressure, which in turn raises the boiling point of water to higher than 100°C. This allows the water and steam inside the cooker to reach higher temperatures, which accelerates the cooking process. The higher temperature results in faster heat transfer to the rice, softening it more quickly than it would at the normal boiling point. This principle is why pressure cookers are efficient for cooking not only rice but also other foods that benefit from being cooked at higher temperatures and in shorter times. Therefore, the correct answer is [B] High pressure increases the boiling point of water. This understanding is essential for efficient cooking and energy conservation in culinary practices.
See lessMan feels discomfort due to humidity. Which of the following is the appropriate reason for this?
Man feels discomfort due to humidity primarily because sweat does not evaporate efficiently in high humidity conditions. Evaporation of sweat from the skin surface is a critical mechanism for cooling the body. In high humidity, the air is already saturated with moisture, significantly slowing down tRead more
Man feels discomfort due to humidity primarily because sweat does not evaporate efficiently in high humidity conditions. Evaporation of sweat from the skin surface is a critical mechanism for cooling the body. In high humidity, the air is already saturated with moisture, significantly slowing down the rate of sweat evaporation. As a result, the body retains more heat, leading to overheating and discomfort. This lack of effective cooling makes the body feel hotter and more uncomfortable compared to dry conditions, where sweat evaporates more readily and provides a cooling effect. Therefore, the correct answer is [C] Sweat not evaporating due to humidity. Understanding this phenomenon is essential for managing heat stress and designing cooling strategies in hot, humid environments, impacting areas such as workplace safety, athletic performance, and general well-being.
See lessA piece of ice is floating in a glass filled with water. When the piece is completely melted, the level of water in the glass
When a piece of ice floating in a glass of water completely melts, the level of water in the glass remains unchanged. This phenomenon can be explained by the principle of buoyancy and the displacement of water. A floating ice cube displaces a volume of water equal to the weight of the ice. When theRead more
When a piece of ice floating in a glass of water completely melts, the level of water in the glass remains unchanged. This phenomenon can be explained by the principle of buoyancy and the displacement of water. A floating ice cube displaces a volume of water equal to the weight of the ice. When the ice melts, it turns into water and occupies the same volume that was initially displaced. Since the density of ice is less than that of water, the melted ice, now in liquid form, fills the exact volume it previously displaced. Therefore, the overall water level in the glass does not change. This principle holds true for any ice floating in a liquid, assuming no additional factors such as temperature changes significantly affecting the water’s volume. Hence, the correct answer is [C] remain unchanged. Understanding this concept illustrates fundamental principles of physics and fluid dynamics.
See less