1. If the doors of a refrigerator kept in the room are left open, the room will gradually get heated. A refrigerator works by removing heat from its interior and releasing it to the surrounding environment through coils at the back or bottom. When the door is left open, the refrigerator's cooling systeRead more

    If the doors of a refrigerator kept in the room are left open, the room will gradually get heated. A refrigerator works by removing heat from its interior and releasing it to the surrounding environment through coils at the back or bottom. When the door is left open, the refrigerator’s cooling system continuously tries to cool the entire room, an impossible task, causing the compressor to run constantly. This results in the refrigerator’s motor generating more heat than it can remove. The heat dissipated from the motor and coils will ultimately increase the room’s temperature. Additionally, the heat expelled by the refrigerator is greater than the cooling effect it produces because of inefficiencies in the refrigeration process. Consequently, the net effect of leaving a refrigerator door open in a room is an increase in the room’s temperature. Therefore, the correct answer is [C] The room will gradually get heated.

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  2. When a table fan is run in a closed room, the air in the room will be heated. This happens because the fan's motor consumes electrical energy and converts some of it into heat due to inefficiencies. While the fan moves air around, creating a cooling sensation on the skin due to increased evaporationRead more

    When a table fan is run in a closed room, the air in the room will be heated. This happens because the fan’s motor consumes electrical energy and converts some of it into heat due to inefficiencies. While the fan moves air around, creating a cooling sensation on the skin due to increased evaporation of sweat, it does not lower the air temperature. Instead, the mechanical energy from the fan blades and the heat generated by the motor slightly increase the room’s overall temperature. In a closed environment with no external cooling or ventilation, this added heat can accumulate over time. Therefore, the correct answer is [A] be heated. The fan primarily enhances air circulation, making it feel cooler to individuals in the room, but it does not reduce the ambient temperature and ultimately contributes to a minor rise in heat due to energy dissipation.

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  3. On cold days, when touching an iron block and a wooden block in the morning, the iron block feels colder because it has higher thermal conductivity than wood; option [B]. Thermal conductivity determines how efficiently a material conducts heat. Iron conducts heat away from the skin faster than woodRead more

    On cold days, when touching an iron block and a wooden block in the morning, the iron block feels colder because it has higher thermal conductivity than wood; option [B]. Thermal conductivity determines how efficiently a material conducts heat. Iron conducts heat away from the skin faster than wood does, resulting in a greater sensation of coldness. This occurs because iron can more effectively transfer heat from the skin to the surrounding environment, creating a perception of lower temperature. Wood, on the other hand, has lower thermal conductivity, so it conducts heat away from the skin more slowly, leading to a lesser sensation of coldness. Therefore, despite both blocks being at the same temperature, the iron block feels colder due to its ability to rapidly draw heat away from the skin, intensifying the perception of cold.

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  4. During strong storms, light thatched or tin roofs often blow away due to a combination of factors ; option [C]. The high velocity air flowing over the roof creates pressure on the roof surface, while the pressure below the roof remains normal, causing an imbalance that can lead to uplift. [B] AdditiRead more

    During strong storms, light thatched or tin roofs often blow away due to a combination of factors ; option [C]. The high velocity air flowing over the roof creates pressure on the roof surface, while the pressure below the roof remains normal, causing an imbalance that can lead to uplift. [B] Additionally, if the roofs are not tied tightly or securely anchored, they are more prone to being lifted by the strong winds. [A] The complexity of the roof shape can exacerbate this vulnerability by providing more surface area for the wind to catch onto. [D] However, it is not accurate to say that thatched roofs automatically blow away in strong winds; their susceptibility depends on various factors such as the quality of construction and the intensity of the storm.

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  5. When two pieces of ice are pressed together, they stick together because of increased pressure, causing the melting point of ice to decrease. The correct option is [A]. When pressure is applied to ice, it lowers the melting point by disrupting the equilibrium between solid and liquid phases. This isRead more

    When two pieces of ice are pressed together, they stick together because of increased pressure, causing the melting point of ice to decrease. The correct option is [A]. When pressure is applied to ice, it lowers the melting point by disrupting the equilibrium between solid and liquid phases. This is due to the pressure-induced stabilization of the liquid phase, which lowers the energy barrier for melting. Consequently, the ice molecules can overcome this barrier more easily, leading to melting even at temperatures below the normal melting point. This phenomenon is known as pressure melting. It’s crucial in various natural processes, such as glacier movement, and has practical applications in ice skating and ice climbing. Understanding pressure’s effect on the melting point of ice is essential in various scientific fields, including climatology and materials science.

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