The best conductor of heat among the options provided is mercury. Mercury is a metal with high thermal conductivity, efficiently transferring heat. In contrast, water, wood, and leather are poor conductors of heat.
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The thermal conductivity of silver is greater than that of copper. Silver has a thermal conductivity of approximately 429 watts per meter Kelvin (W/mK), while copper’s thermal conductivity is about 401 W/mK.
A bolometer measures thermal radiation. It detects and quantifies infrared or heat radiation emitted by objects. By monitoring changes in electrical resistance when exposed to thermal radiation, bolometers determine radiation intensity. They are essential in various fields for precise measurement ...
A small space is left at the joint between two railway tracks because the metal expands when heated and contracts when cooled. This prevents the tracks from buckling in the heat or creating gaps in the cold, ensuring safe and ...
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 4°C. This is because water reaches its maximum density at 4°C and sinks ...
When water freezes due to cold in winter, fishes and other aquatic organisms can survive because only the upper layer of water freezes. This insulating ice layer keeps the water below from freezing, maintaining a habitable environment.
The method of transmission of heat includes conduction, convection, and radiation. Conduction occurs in solids, convection in fluids, and radiation through electromagnetic waves. Therefore, all three methods together describe how heat can be transmitted.
In conduction, particles of matter do not move on their own from one place to another. Instead, heat is transferred through direct contact between particles. The particles vibrate and transfer energy without significant movement.
Heat is primarily transferred in liquids and gases by convection. Convection involves the movement of fluid particles, carrying heat as they circulate. While conduction can occur to some extent, it is less efficient, and radiation plays a minor role.
To reduce angular speed on a freely rotating platform, a person should spread their hands outwards. This increases the moment of inertia, causing the rotational speed to decrease according to the conservation of angular momentum.