Modes of Heat Transfer

HEAT

​Heat will always transfer from Hot object to Cold Object

​ HOT ----> COLD

​Modes of Heat Transfer:

​1. Conduction

​2. Convection

​3. Radiation

Multiple Choice

Heat always flows

• from a colder object to a hotter object

• from a hotter object to a colder object

• in both the directions

• heat never flows from one object to other

Multiple Choice

Which mode of heat transfer happens in solids?

• Conduction

• Convection

• Radiation

• None

Multiple Choice

Which mode of  heat transfer do not require any medium?

• Conduction

• Convection

• Radiation

• None

Multiple Choice

Why should we wear cotton clothes in summer ?

• Easy to wash

• Traps heat inside

• Absorbs sweat and let air pass through it

• None

Multiple Choice

Why should we wear wollen clothes in winter?

• Easy to wash

• Traps heat inside

• Absorbs sweat and let air pass through it

• None

​Degree of hotness or coldness of an object is called as Temperature

​Temperature is measured by a device called thermometer.

​

​Types of Thermometer:

​

1. Laboratory Thermometer

2. Clinical Thermometer

Clinical Thermometer​

• It is commonly used in hospitals

• ​It measures our body temperature.

• They measure short range of temperature.​ (35°C to 42°C)

Laboratory Thermometer​

• It is commonly used in laboratories.

• ​It is used for laboratory experiments.

• They measure wider temperature range. (-10°C to 110°C)

DIFFERENCES​

Clinical Thermometer​ and  Laboratory Thermometer​

1. Both are made up of thin glass narrow tube and consist of a long narrow tube made up of glass. 

​

2. Both of the thermometers have a bulb at one end.

3. Both the meters give readings with the mercury that is inside the thermometer.

SIMILARITIES

Multiple Choice

What is the normal temperature of a healthy person?

• 37°C

• 37°F

• 37°K

• None

Multiple Choice

Which one is filled in the bulb of a thermometer?

• Mercury

• Lead

• Copper

• Silver

Multiple Choice

Which of the following thermometer contains mercury?

• Clinical thermometer

• Laboratory thermometer

• Both Clinical and Laboratory thermometer

Multiple Choice

ASSERTION: MERCURY CAN BE USED IN THERMOMETERS

REASON: IT EXPANDS ON COOLING AND CONTRACTS ON HEATING

• ONLY R IS TRUE

• Both are true and R is correct explanation for A

• BOTH A AND R ARE CORRECT

• ONLY A IS TRUE

Multiple Choice

Assertion (A): Temperature is a measure of degree of hotness of our body. Reason (R): We use a clinical thermometer to measure the degree of hotness of our body. 

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.