Class 7 Science Chapter 3 MCQ

There are many circumstances where clinical thermometer can break. Here, all the options are correct. Your answer will be option [D].

The temperature of another object may not be the same as that of the bulb of the thermometer. When bulb is brought in contact with that object, the temperature of the bulb changes. So, the level of mercury also changes.

Energy does transfer between the two bodies continuously even if they are at the same temperature. There is always exchange of packets of energy at the interface of each and everybody. But there is no net energy transfer between the bodies.

Conduction occurs when two objects at different temperatures are in contact with each other. Heat flows from the warmer to the cooler object until they are both at the same temperature. Conduction is the movement of heat through a substance by the collision of molecules. This process continues until heat energy from the warmer object spreads throughout the cooler object, like the heat from the milk spreading throughout the metal spoon dipped in it. Hence, option [A] is correct.

Wood, plastic are the non-conductor of heat and electricity. When wooden spoon is used to prepare vegetables, its other end does not become hot.

The SI unit of heat is Joule (J) and the SI unit of temperature is Kelvin (K). Only option [A] is incorrect. Here, rest of all statements are correct. Hence, your answer will be option [A].

Thermometer is a device which is used to measure the degree of coldness or hotness of an object. Rest all are incorrect. Hence, your answer will be option [C].

A land which is surrounded by water heated not by convection. From the sun the heat comes to us by the process of radiation and heated all the objects which is present on the earth. Therefore, a land which is surrounded by water heated by radiation not by convection.

A clinical thermometer consists a uniform glass tube. Rest all the options are correct. Hence, your answer will be option [A].

Thermo flask is a special kind of class for keeping liquids. It consists of a double walled glass cylinder. A vacuum is created in the space between the two walls. Hence, radiation is actually minimized. Hence, your answer will be option [C].

Since, a marble tile is a good conductor of heat as compared to the wood, therefore a marble tile will allow heat to pass through itself easily, keeping it a cool on a winter morning.

Most of us use the word ‘heat’ to mean something that feels warm, but science defines heat as the flow of energy from a warm object to a cooler object. Heat spontaneously passes to its surroundings with medium or without any medium. Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases.

Here, all the statements are correct about “Heat”. Hence, your answer will be option [D].

Mercury is the only metal which is found in liquid state at room temperature and it expands when it receives heat. We should avoid keeping the clinical thermometer in the sun or near a flame because the clinical thermometer is designed to measure the temperature of human body only. This thermometer has the range of 35 degree Celsius to 42 degree Celsius. It may break in the sun or near a flame.

This can be done by constructing outer walls by special bricks. So, that they have trapped layers of air. The way of doing this is to use hollow bricks, which are available these days. Hence, your answer will be option [C].

We know that wood is non-conductor of heat or cold. It acts as an insulator. So, when wooden spoon is dipped in a cup of ice cream its other end does not become cold. Hence, your answer will be option [D].

There are many conditions to break clinical thermometer as when kept in Sun, when hits by hard objects and when dipped in hot tea. Hence, your answer will be option [D].

Clinical thermometer and digital thermometer are used to measure body temperature and laboratory thermometer is used to measure the temperature of boiling water or any object other than human body.

(36.4 + 37.4 + 36.6) degree Celsius = 110.4 For getting average body tem we should divide: “Total temperature” by “Number of times” Therefore, 110.4/3 = 36.8 degree Celsius

Energy does transfer between the two bodies continuously even if they are at the same temperature but there is no net energy transfer between the bodies. Therefore, we can say that no energy flow from iron ball to water or from water to iron ball. Hence, your answer will be option [B].

The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. From the sun the heat comes to us by this process which is known as radiation. When we sit in front of a room heater, we get heat by this process. All the objects are heated from the rays of sun by this process.

We know that Mercury is liquid at room temperature and expand with heat. Expansion may apply pressure to break it.

Clothes of white colour reflects more heat than blue colours. Iron is the poor conductor of heat than aluminium. Our body is a good conductor of electricity. Hence, your answer will be option [D].

We are advised not to hold the thermometer bulb while reading it, as the level of mercury increases from the actual reading due to our body temperature. Hence, your answer will be option [D].

We will prefer white fabric tent in case of summer because it reflects all the radiations from the sun and keeps us cool inside the tent.