Heat ICSE Class-7th Concise Selina Physics Solutions

Heat ICSE Class-7th Concise Selina Physics Solutions Chapter-5. We Provide Step by Step Answer of Objective, True False , Fill in the blanks,Match the following , Short/Long Answer Type of Exercise-5 Heat . Visit official Website  CISCE  for detail information about ICSE Board Class-7.

Heat ICSE Class-7th Concise Selina Physics Solutions Chapter-5


A. Objective Questions Chapter-5 Heat ICSE Concise Selina

1. Write true or false for each statement

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

(b) Heat flows from a body at a high temperature to a body at a low temperature when they are kept in contact. .
Answer. True.

(c) All solids expand by the same amount when heated to the same rise in temperature.
Answer. False.

(d) Telephone wires are kept tight between the two poles in summer.
Answer. False.

(e) Equal volumes of different liquids expand by different amounts when they are heated to the same rise in temperature.
Answer. True.

(f) Solids expand the least and gases expand the most on being heated.
Answer. True.

(g) A mercury thermometer makes use of the property of expansion of liquids on heating.
Answer. True.

(h) Kerosene contracts on heating.
Answer. False.

(i) Water is a bad conductor of heat.
Answer. True.

(j) Medium is necessary for the transfer of heat by radiation.
Answer. False.

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(k) Land and sea breezes are convection currents of cold and warm air.
Answer. True.

(l) Liquids are heated by conduction and radiation.
Answer. False.

(m) Black surfaces are the poor absorbers of heat radiations.
Answer. False.


2. Fill in the blanks Heat ICSE Class-7th Concise 

(a) Heat is a form of …..
(b) ….. determines the degree of hotness or coldness of a body.
(c) On heating a body, its temperature …..
(d) We use a ….. for measuring the temperature of a body.
(e) The S.I. unit of temperature is…..
(f) In a thermometer, the commonly used liquid is ……
(g) The temperature of a normal human body is…...
(h) A person is said to have fever if his body temperature is more than ….
(i) A hot metallic piece is placed in tap water contained in a bucket. Heat will flow from ….. to …..
(j) The temperature of boiling water is …..
(k) Liquids expand…. than the solids.
(l) Gases expand …. than the liquids.
(m) Heat transfer in solids is by …..
(n) Heat transfer in liquids and gases is by …..
(o)Metals are …. of heat.

(p) Still air is an …. of heat.
(q) Black and dull surfaces are …… of heat.

Ans Fill in the blanks

(a) Heat is a form of energy.
(b) Temperature determines the degree of hotness or coldness of a body.
(c) On heating a body, its temperature rises.
(d) We use a thermometer for measuring the temperature of a body.
(e) The S.I. unit of temperature is kelvin.
(f) In a thermometer, the commonly used liquid is mercury.
(g) The temperature of a normal human body is 37 °C.
(h) A person is said to have fever if his body temperature is more than 98.6
(i) A hot metallic piece is placed in tap water contained in a bucket. Heat will flow from metallic piece to water.
(j) The temperature of boiling water is 100°C.
(k) Liquids expand more than the solids.
(l) Gases expand more than the liquids.
(m) Heat transfer in solids is by conduction.
(n) Heat transfer in liquids and gases is by convection.
(o)Metals are conductors of heat.

(p) Still air is an insulator of heat.
(q) Black and dull surfaces are good absorbers of heat.


3. Match the following Heat ICSE Class-7th Concise 

Match the following


4. Select the correct alternative Heat ICSE Class-7th Concise 

(a) 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

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3.-heat flows from water to ice if water is more

4.-heat flows from ice to water if ice is more

Answer

heat flows from water to ice

(b) The temperature of pure melting ice is

  1. 0°C
  2.  100°C
  3.  95°C
  4.  98.6°F

Answer

0°C

(c) A thermometer uses

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

Answer

A little space is left between two rails on a railway track

(d) 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

Answer

A little space is left between two rails on a railway track

(e) Heat in a liquid is transferred by

  1.  conduction
  2. convection
  3.  radiation
  4.  conduction and radiation

Answer

convection

(f) In the process of convection, heat travels

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

Answer

upwards

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

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

Answer

conduction and convection


B. Short/Long Answer Questions Heat ICSE Class-7th Concise 

Question 1.

What is heat ? State its S.I. unit.
Answer:
Heat is a form of energy which flows. It is the energy of motion of molecules constituting the body.
The unit of heat is same as that of energy, The S.I. unit of heat is joule (abbreviated as J) and other common units of heat are calorie and kilo calorie, where 1 kcal = 1000 cal.

Question 2.

What is meant by the term temperature.

Answer:
Temperature is a quantity which tells the thermal state of a body (i.e. the degree of hotness or coldness). It determines the direction of flow of heat when the two bodies at different temperatures are placed in contact.

Question 3.

State the three units of temperature.
Answer:
The S.I. unit of temperature is kelvin or K. The other most common unit of temperature is degree Celsius (°C) and degree Fahrenheit (°F).

Question 4.

Name the instrument used to measure the temperature of a body.
Answer:
To measure the temperature of a body with the help of a thermometer.

Question 5.

Name two scales of temperature. How are they inter-related?
Answer:
Two scales of temperature are
(i) Celsius (ii) Fahrenheit
Relation:

Ans 5 heat energy

Question 6.

How is the size of a degree defined on a Celsius scale ?
Answer:
The interval between the ice point and steam point divided by 100 (hundred) equal parts is called a degree on the Celsius scale.

Question 7.

How is the size of a degree defined on a Fahrenheit scale?
Answer:
The interval between the ice point and steam point divided into 180 equal parts is called a degree on the Fahrenheit scale.

Question 8.

State the temperature of (i) ice point and (ii) steam point, on the Celsius scale.
Answer:
(i) Ice point. Is the the mark on Celsius scale at which ice melts. Ice point on the Celsius scale is 0°C.

(ii) Steam point. On the Celsius scale is the mark at which water changes into steam at normal atmospheric pressure. On Celsius scale it is 100°C.

Question 9.

Write down the temperature of (i) lower fixed point, and (ii) upper fixed point, on the Fahrenheit scale.
Answer:
Lower fixed point: On the Falirenheit scale is the mark at which pure ice melts. It is 32°F on Fahrenheit scale.
Upper fixed point: On the Fahrenheit scale is the mark at which water starts changing into steam at normal atmospheric pressure. It is 212°F.

Question 10.

What is the Celsius scale of temperature ?
Answer:
Celsius scale is that which has ice point as 0°C and steam point marked as 100°C.

Question 11.

What is the Fahrenheit scale of temperature ?
Answer:
Fahrenheit scale is that which has ice point as 32°F and the steam point marked as 100°C.

Question 12.

What is the Kelvin scale of temperature ?
Answer:
On Kelvin scale of temperature zero mark is when no molecular motion occurs. Ice point is at 273 and steam point is at 373 K. Thus 0 K = – 273°C and one degree on Kelvin scale is same as one degree on Celsius scale.

Question 13.

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.

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