Heat Test - 3

A clinical thermometer has a kink near the bulb. The function of kink is to prevent mercury level from falling on its own. So that the mercury does not rise or fall when taken out of mouth.

Hence, option A is the correct answer.

The liquid metal inside the thermometer is mercury. Mercury is one of the very few metal that stays liquid at room temperature. Therefore, it is suitable for the use of mercury in thermometer. Also the mercury has small coefficient of heat expansion which makes it sensitive enough to the change on the temperature.

Thus option A is the correct answer.

The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. When we sit in front of a room heater, we get heat by this process. A hot utensil kept away from the flame cools down as it transfers heat to the surroundings by radiation.

Therefore, option C is the correct answer.

In the winter, we use woolen clothes. Wool is a poor conductor of heat. Moreover, there is air trapped in between the wool fibers. This air prevents the flow of heat from our body to the cold surroundings. So, we feel warm.

Thus option D is the correct answer.

At night it is exactly the reverse. The water cools down more slowly than the land. So, the cool air from the land moves towards the sea. This is called the land breeze land breeze.

Hence option A is the correct answer.

When water is heated, the water near the flame gets hot. Hot water rises up. The cold water from the sides moves down towards the source of heat. This water also gets hot and rises and water from the sides moves down. This process continues till the whole water gets heated. This mode of heat transfer is known as convection.

A white shirt is usually preferred over dark clothes during a hot summer day because white color reflect the sun’s energy. During summer most of the people prefer to wear White dress because “White reflects lights”. Whereas, a black object is black because it's absorbing all the light; it's not reflecting any color. Dark clothes heat up faster than white clothes in the sun. So in order to keep your body temperature normal it’s better to wear white dress.

Hence, option B is the correct answer.

The heat energy from the sun cannot reach the earth’s surface by conduction or convection as there is no medium such as air in most part of the space between the earth and the sun. From the sun the heat comes to us by another process known as radiation. The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. When we sit in front of a camp fire, we get heat by this process.

Hence, option A is the correct answer.

Fahrenheit and degree Celsius are two units of measuring the temperature. If the teacher says the measurement is true, then Ram’s thermometer must have measured the temperature in degree Fahrenheit.

Hence, they both are measuring the same temperature with an equipment that has different units of measurement.

Thus, option C is the correct answer.