ICSE Class 7CISCE
Share

# Selina solutions for Class 7 Physics chapter 5 - Heat

## Chapter 5: Heat

#### Selina solutions for Class 7 Physics Chapter 5 [Page 0]

Write true or false

On touching a lump of ice, we feel cold because some heat passes from our body to the ice.

. Write true or false

Heat flows from a body at a high temperature to a body at a low temperature when they are kept in contact.

Write true or false

All solids expand by the same amount when heated to the same rise in temperature.

Write true or false

Telephone wires are kept tight between the two poles in summer.

Write true or false

Equal volumes of different liquids expand by different amounts when they are heated to the same rise in temperature.

Write true or false

Solids expand the least and gases expand the most on being heated.

Write true or false

A mercury thermometer makes use of the property of expansion of liquids on heating.

Write true or false

Kerosene contracts on heating.

Write true or false

Water is a bad conductor of heat.

Write true or false

Medium is necessary for the transfer of heat by radiation.

Write true or false

Land and sea breezes are convection currents of cold and warm air.

Write true or false

Liquids are heated by conduction and radiation.

Write true or false

Black surfaces are the poor absorbers of heat radiations.

Fill in the blank

Heat is a form of ............

Fill in the blank

.......................determines the degree of hotness or coldness of a body.

Fill in the blank

On heating a body, its temperature.......

Fill in the blank

We use a ...................for measuring the temperature of a body.

Fill in the blank

The S.I. unit of temperature is .............

Fill in the blank

In a thermometer, the commonly used liquid is ............

Fill in the blank

The temperature of a normal human body is............

Fill in the blank

A person is said to have fever if his body temperature is more than .............

Fill in the blank

A hot metallic piece is placed in tap water contained in a bucket. Heat will flow from ................ to ...............

Fill in the blank

The temperature of boiling water is ............

Fill in the blank

Liquids expand .............than the solids.

Fill in the blank

Gases expand ........... than the liquids.

Fill in the blank

Heat transfer in solids is by ................

Fill in the blank

Heat transfer in liquids and gases is by............

Fill in the blank

Metals are ..................of heat.

Fill in the blank

Still air is an .............of heat.

Fill in the blank

Black and dull surfaces are ......................of heat.

Match the following

 Column A Column B 1. mercury 1. insulator 2. wood 2. water from 0°C to 4°C 3. Aluminum 3.absorbs 4. contracts 4.conductor 5.black surface 5. Thermometer

Select the correct alternative

If we add a lump of ice to a tumbler containing water,

1. heat flows from water to ice
2.  heat flows from ice to water
3.  heat flows from water to ice if water is more
4.  heat flows from ice to water if ice is more

Select the correct alternative

The temperature of pure melting ice is

1.  0°C
2.  100°C
3.  95°C
4.  98.6°F

Select the correct alternative

A thermometer uses

1.  water
2. mercury
3.  air
4.  none of the above

Select the correct alternative

Which of the statement is correct

1.  Iron rims are cooled before they are placed on cart wheels
2.  A glass stopper gets tight on warming the neck of the bottle
3.  Telephone wires sag in winter, but become tight in summer
4. A little space is left between two rails on a railway track

Select the correct alternative

Heat in a liquid is transferred by

1.  conduction
2. convection

Select the correct alternative

In the process of convection, heat travels

1.  sideways
2.  downwards
3. upwards
4.  in all directions

Select the correct alternative

The vacuum kept in between the walls of a thermos flask reduces the heat transfer by

1.  conduction only
2.  convection only
4. conduction and convection

#### Selina solutions for Class 7 Physics Chapter 5 [Page 0]

What is heat ? State its S.I. unit.

What is meant by the term temperature.

State the three units of temperature.

Name the instrument used to measure the temperature of a body.

Name two scales of temperature. How are they inter-related?

How is the size of a degree defined on a Celsius scale ?

How is the size of a degree defined on a Fahrenheit scale?

State the temperature of  ice point on the Celsius scale.

State the temperature of steam point on the Celsius scale.

Write down the temperature of lower fixed point , on the Fahrenheit scale.

Write down the temperature of upper fixed point,, on the Fahrenheit scale.

What is the Celsius scale of temperature ?

What is the Fahrenheit scale of temperature ?

What is the Kelvin scale of temperature ?

The fig. shows a glass tumbler containing hot milk which is placed in a tub of cold water. State the direction in which heat will flow.

Draw a neat labelled diagram of a laboratory thermometer.

Write down the body temperature of a healthy person.

What do you understand by thermal expansion of a substance ?

Name two substances which expand on heating.

Why do telephone wires sag in summer ?

Iron rims are heated before they are fixed on the wooden wheels. Explain the reason.

Why are gaps left between successive rails on a railway track ?

A glass stopper stuck in the neck of a bottle can be removed by pouring hot water on the neck of the bottle. Explain why ?

Why is a cement floor laid in small pieces with gaps in between?

One end of a steel girder in a bridge is not fixed, but is kept on roliers. Give the reason.

Describe one experiment to show that liquids expand on heating.

State one application of thermal expansion of liquids.

Describe an experiment to show that air expands on heating.

An Empty Glass Bottle is Fitted with a Narrow Tube at Its Mouth When the Bottle is Heated, Bubbles of Air Are Seen Escaping into the Water. Explain the Reason.

State which expands more, when heated to the same temperature : solid, liquid or gas ?

Name the three modes of transfer of heat.

Name the mode of transfer of heat in the following :
(a) solid,
(b) liquid,
(c) gas
(d) vacuum

What are the good and bad conductors of heat ? Give two examples of each.

Name a liquid which is a good conductor of heat.

Name a solid which is a good conductor of heat.

Select good and bad conductors of heat from the following :
copper, mercury, wood, iron, air, saw-dust, cardboard, silver, plastic, wool.

Why is an oven made of double walls with the space in between filled with cork ?

Why do we use cooking utensils made up of copper.

Why is a tea kettle provided with an ebonite handle ?

In summer, ice is kept wrapped in a gunny bag. Explain the reason.

Explain why  we wear woolen clothes in winter.

Explain why  the water pipes are covered with cotton during very cold weather.

Why are quilts filled with fluffy cotton ?

State the direction of heat transfer by way of convection.

Why is a ventilator provided in a room ?

Why are chimneys provided over furnace in factories ?

What are the land and sea breezes ? Explain their formation.

Why is the freezing chest in a refrigerator fitted near its top?

Explain briefly the process of heat transfer by radiation.

Give one example of heat transfer by radiation.

Why do we prefer to wear white or light coloured clothes in summer and black or dark coloured clothes in winter ?

The bottom of a cooking utensil is painted black. Give the reason.

Draw a labelled diagram of a thermo flask. Explain how the transfer of heat by conduction, convection and radiation is reduced to a minimum in it.

#### Selina solutions for Class 7 Physics Chapter 5 [Page 0]

The temperature of a body rises by 1°C. What is the corresponding rise on the (a) Fahrenheit scale (b) Kelvin scale?

The temperature rises by 18°F. What is the rise on the Celsius scale ?

Convert 5°F to the Celsius scale.

Convert 40°C to the (a) Fahrenheit scale (b) Kelvin Scale.

Convert – 40°F to the Celsius scale.

## Selina solutions for Class 7 Physics chapter 5 - Heat

Selina solutions for Class 7 Physics chapter 5 (Heat) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Selina Concise Physics - Middle School for Class 7 solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Class 7 Physics chapter 5 Heat are Heat as a Form of Energy and Its Units, Joule(J) and Calorie (Cal)., Different Units of Temperature (°C, °F, K)., Effects of Heat - Change in Temperature, Effects of Heat - Change in Size (Expansion and Contraction)., Effects of Heat - Change in State, Effects of Heat - Good Conductors and Bad Conductors of Heat and Their Examples, Effects of Heat - Choice of Conductors and Insulators in Day to Day Life (Pan Handles, Metal Cooking Utensils Etc.), Methods of Heat Transfer - Conduction, Methods of Heat Transfer - Convection, Methods of Heat Transfer - Radiation, Concept of Heat.

Using Selina Class 7 solutions Heat exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 7 prefer Selina Textbook Solutions to score more in exam.

Get the free view of chapter 5 Heat Class 7 extra questions for Physics and can use Shaalaa.com to keep it handy for your exam preparation

S