Selina Textbook Solutions: Physical Quantities and Measurement | Physics Class 7 ICSE PDF Download

 Page 1


 
Physical Quantities and Measurement 
Points to Remember 
? The mass of a body is the quantity of matter contained in a body regardless of its 
volume or any force acting on it. 
?  The weight of a body is the force with which every body is attracted towards its 
centre. 
?  The unit of mass in S.I. system is kilogram (kg). Higher units of mass are quintal 
and metric tonne. 
?  The weight of body changes with acceleration due to gravity. 
?  Weight is zero at the centre of the earth. 
?  Mass per unit volume of a substance is called density of the body. 
?  The unit of density in S.I. system is kg m
-3
 and gcm
-3
 in C.G.S. system. 
?  The density in S.I. system is 1000 × numerical value in C.G.S. system. 
?  The density of liquids and gases decreases or increases with the rise or fall in 
temperature. 
? The cycle of upward and downward movements of the fluid form currents in the 
medium which are known as convectional currents. 
Test Yourself 
A. Objective Questions  
1. Write true or false for each statement 
(a) The S.I. unit of volume is litre. 
Answer. False. 
The S.I. unit of volume is cubic metre. 
(b) A measuring beaker of capacity 200 ml can measure only the volume. 200 ml of a 
liquid. 
Answer. True. 
(c) cm2 is a smaller unit of area than m
2
. 
Answer. True. 
(d) Equal volumes of two different substances have equal masses. 
Answer. False. 
Equalvolumes of two different substances have different masses. 
Page 2


 
Physical Quantities and Measurement 
Points to Remember 
? The mass of a body is the quantity of matter contained in a body regardless of its 
volume or any force acting on it. 
?  The weight of a body is the force with which every body is attracted towards its 
centre. 
?  The unit of mass in S.I. system is kilogram (kg). Higher units of mass are quintal 
and metric tonne. 
?  The weight of body changes with acceleration due to gravity. 
?  Weight is zero at the centre of the earth. 
?  Mass per unit volume of a substance is called density of the body. 
?  The unit of density in S.I. system is kg m
-3
 and gcm
-3
 in C.G.S. system. 
?  The density in S.I. system is 1000 × numerical value in C.G.S. system. 
?  The density of liquids and gases decreases or increases with the rise or fall in 
temperature. 
? The cycle of upward and downward movements of the fluid form currents in the 
medium which are known as convectional currents. 
Test Yourself 
A. Objective Questions  
1. Write true or false for each statement 
(a) The S.I. unit of volume is litre. 
Answer. False. 
The S.I. unit of volume is cubic metre. 
(b) A measuring beaker of capacity 200 ml can measure only the volume. 200 ml of a 
liquid. 
Answer. True. 
(c) cm2 is a smaller unit of area than m
2
. 
Answer. True. 
(d) Equal volumes of two different substances have equal masses. 
Answer. False. 
Equalvolumes of two different substances have different masses. 
(e) The S.I. unit of density is g cm
-3
. 
Answer. False. 
The S.I. unit of density is Kg m
-3
. 
(f) 1 g cm
-3
 = 1000 kg m
-3
. 
Answer. True. 
(g) The density of water is maximum at 4°C. 
Answer. True. 
(h) The speed 5 ms
-1
 is less than 25 km h
-1
. 
Answer. True. 
(i) The S.I. unit of speed is ms
-1
. 
Answer. True 
2. Fill in the blanks 
(a) l m
3
 = 10
6
 cm
3
 
(b) The volume of an irregular solid is determined by the method of displacement of 
liquid. 
(c) Volume of a cube = (one side) 
(d) The area of an irregular lamina is measured by using a grapl paper. 
(e) Mass = density × volume. 
(f) The S.I. unit of density is kg m
-3
. 
(g) 1 g cm
-3
 = 1000 kg m
-3
. 
(h) 36 km h
-1
 = 10 ms
-1
. 
(i) Distance travelled d = speed v × time t. 
3. Match the following 
Page 3


 
Physical Quantities and Measurement 
Points to Remember 
? The mass of a body is the quantity of matter contained in a body regardless of its 
volume or any force acting on it. 
?  The weight of a body is the force with which every body is attracted towards its 
centre. 
?  The unit of mass in S.I. system is kilogram (kg). Higher units of mass are quintal 
and metric tonne. 
?  The weight of body changes with acceleration due to gravity. 
?  Weight is zero at the centre of the earth. 
?  Mass per unit volume of a substance is called density of the body. 
?  The unit of density in S.I. system is kg m
-3
 and gcm
-3
 in C.G.S. system. 
?  The density in S.I. system is 1000 × numerical value in C.G.S. system. 
?  The density of liquids and gases decreases or increases with the rise or fall in 
temperature. 
? The cycle of upward and downward movements of the fluid form currents in the 
medium which are known as convectional currents. 
Test Yourself 
A. Objective Questions  
1. Write true or false for each statement 
(a) The S.I. unit of volume is litre. 
Answer. False. 
The S.I. unit of volume is cubic metre. 
(b) A measuring beaker of capacity 200 ml can measure only the volume. 200 ml of a 
liquid. 
Answer. True. 
(c) cm2 is a smaller unit of area than m
2
. 
Answer. True. 
(d) Equal volumes of two different substances have equal masses. 
Answer. False. 
Equalvolumes of two different substances have different masses. 
(e) The S.I. unit of density is g cm
-3
. 
Answer. False. 
The S.I. unit of density is Kg m
-3
. 
(f) 1 g cm
-3
 = 1000 kg m
-3
. 
Answer. True. 
(g) The density of water is maximum at 4°C. 
Answer. True. 
(h) The speed 5 ms
-1
 is less than 25 km h
-1
. 
Answer. True. 
(i) The S.I. unit of speed is ms
-1
. 
Answer. True 
2. Fill in the blanks 
(a) l m
3
 = 10
6
 cm
3
 
(b) The volume of an irregular solid is determined by the method of displacement of 
liquid. 
(c) Volume of a cube = (one side) 
(d) The area of an irregular lamina is measured by using a grapl paper. 
(e) Mass = density × volume. 
(f) The S.I. unit of density is kg m
-3
. 
(g) 1 g cm
-3
 = 1000 kg m
-3
. 
(h) 36 km h
-1
 = 10 ms
-1
. 
(i) Distance travelled d = speed v × time t. 
3. Match the following 
 
4. Select the correct alternative  
(a) One litre is equal to : 
1.  1 cm
-3
 
2. 1 m
3
 
3.  10
-3  
cm
3
 
4. 10
-3
 m
3
 
(b) A metallic piece displaces water of volume 15 ml. The volume of piece is : 
1.  15 cm
3
 
2.  15 m
3
 
3.  15 × 10
3
 cm
3
 
4.  15 × 10
3
 cm
3
 
(c) A piece of paper of dimensions 1.5 m x 20 cm has area : 
1.  30 m2 
2.  300 cm2 
3.  0.3 m2 
4.  3000 m3 
Page 4


 
Physical Quantities and Measurement 
Points to Remember 
? The mass of a body is the quantity of matter contained in a body regardless of its 
volume or any force acting on it. 
?  The weight of a body is the force with which every body is attracted towards its 
centre. 
?  The unit of mass in S.I. system is kilogram (kg). Higher units of mass are quintal 
and metric tonne. 
?  The weight of body changes with acceleration due to gravity. 
?  Weight is zero at the centre of the earth. 
?  Mass per unit volume of a substance is called density of the body. 
?  The unit of density in S.I. system is kg m
-3
 and gcm
-3
 in C.G.S. system. 
?  The density in S.I. system is 1000 × numerical value in C.G.S. system. 
?  The density of liquids and gases decreases or increases with the rise or fall in 
temperature. 
? The cycle of upward and downward movements of the fluid form currents in the 
medium which are known as convectional currents. 
Test Yourself 
A. Objective Questions  
1. Write true or false for each statement 
(a) The S.I. unit of volume is litre. 
Answer. False. 
The S.I. unit of volume is cubic metre. 
(b) A measuring beaker of capacity 200 ml can measure only the volume. 200 ml of a 
liquid. 
Answer. True. 
(c) cm2 is a smaller unit of area than m
2
. 
Answer. True. 
(d) Equal volumes of two different substances have equal masses. 
Answer. False. 
Equalvolumes of two different substances have different masses. 
(e) The S.I. unit of density is g cm
-3
. 
Answer. False. 
The S.I. unit of density is Kg m
-3
. 
(f) 1 g cm
-3
 = 1000 kg m
-3
. 
Answer. True. 
(g) The density of water is maximum at 4°C. 
Answer. True. 
(h) The speed 5 ms
-1
 is less than 25 km h
-1
. 
Answer. True. 
(i) The S.I. unit of speed is ms
-1
. 
Answer. True 
2. Fill in the blanks 
(a) l m
3
 = 10
6
 cm
3
 
(b) The volume of an irregular solid is determined by the method of displacement of 
liquid. 
(c) Volume of a cube = (one side) 
(d) The area of an irregular lamina is measured by using a grapl paper. 
(e) Mass = density × volume. 
(f) The S.I. unit of density is kg m
-3
. 
(g) 1 g cm
-3
 = 1000 kg m
-3
. 
(h) 36 km h
-1
 = 10 ms
-1
. 
(i) Distance travelled d = speed v × time t. 
3. Match the following 
 
4. Select the correct alternative  
(a) One litre is equal to : 
1.  1 cm
-3
 
2. 1 m
3
 
3.  10
-3  
cm
3
 
4. 10
-3
 m
3
 
(b) A metallic piece displaces water of volume 15 ml. The volume of piece is : 
1.  15 cm
3
 
2.  15 m
3
 
3.  15 × 10
3
 cm
3
 
4.  15 × 10
3
 cm
3
 
(c) A piece of paper of dimensions 1.5 m x 20 cm has area : 
1.  30 m2 
2.  300 cm2 
3.  0.3 m2 
4.  3000 m3 
(d) The correct relation is : 
1.  d = M × V 
2.  M = d × Y   
3.  V = d × M 
4.  d = M + V 
(e) The density of alcohol is 0.8 g cm-3. In S.I. unit, it will be : 
1.  0.8 kg m
-3
 
2.  0.0008 kg m
-3
 
3.  800 kg m
-3
 
4.  8 x 10
3
 kg m
-3
 
(f) The density of aluminium is 2.7 g cm-3 and of brass is 8.4 g cm
-3
. For the same 
mass, the volume of: 
1.  both will be same 
2.  aluminium will be less than that of brass 
3.  aluminium will be more than that of brass 
4.  nothing can be said. 
(g) A block of wood of density 0.8 g cm
-3
 has a volume of 60 cm
3
. The mass of block will 
be : 
1.  60.8 g 
2.  75 g 
3.  48 g 
4.  0.013 g 
(h) The correct relation for speed is 
1.  Speed = distance x time 
2.  speed = distance / time 
3.  speed = time / distance 
4.  speed = 1 / distance x time 
(i) A boy travels a distance 150 m in 1 minute. His speed is 
1.  150 m s
-1
 
2.  2.5 m s
-1
 
3.  25 m s
-1
 
4.  9 m s
-1
 
Page 5


 
Physical Quantities and Measurement 
Points to Remember 
? The mass of a body is the quantity of matter contained in a body regardless of its 
volume or any force acting on it. 
?  The weight of a body is the force with which every body is attracted towards its 
centre. 
?  The unit of mass in S.I. system is kilogram (kg). Higher units of mass are quintal 
and metric tonne. 
?  The weight of body changes with acceleration due to gravity. 
?  Weight is zero at the centre of the earth. 
?  Mass per unit volume of a substance is called density of the body. 
?  The unit of density in S.I. system is kg m
-3
 and gcm
-3
 in C.G.S. system. 
?  The density in S.I. system is 1000 × numerical value in C.G.S. system. 
?  The density of liquids and gases decreases or increases with the rise or fall in 
temperature. 
? The cycle of upward and downward movements of the fluid form currents in the 
medium which are known as convectional currents. 
Test Yourself 
A. Objective Questions  
1. Write true or false for each statement 
(a) The S.I. unit of volume is litre. 
Answer. False. 
The S.I. unit of volume is cubic metre. 
(b) A measuring beaker of capacity 200 ml can measure only the volume. 200 ml of a 
liquid. 
Answer. True. 
(c) cm2 is a smaller unit of area than m
2
. 
Answer. True. 
(d) Equal volumes of two different substances have equal masses. 
Answer. False. 
Equalvolumes of two different substances have different masses. 
(e) The S.I. unit of density is g cm
-3
. 
Answer. False. 
The S.I. unit of density is Kg m
-3
. 
(f) 1 g cm
-3
 = 1000 kg m
-3
. 
Answer. True. 
(g) The density of water is maximum at 4°C. 
Answer. True. 
(h) The speed 5 ms
-1
 is less than 25 km h
-1
. 
Answer. True. 
(i) The S.I. unit of speed is ms
-1
. 
Answer. True 
2. Fill in the blanks 
(a) l m
3
 = 10
6
 cm
3
 
(b) The volume of an irregular solid is determined by the method of displacement of 
liquid. 
(c) Volume of a cube = (one side) 
(d) The area of an irregular lamina is measured by using a grapl paper. 
(e) Mass = density × volume. 
(f) The S.I. unit of density is kg m
-3
. 
(g) 1 g cm
-3
 = 1000 kg m
-3
. 
(h) 36 km h
-1
 = 10 ms
-1
. 
(i) Distance travelled d = speed v × time t. 
3. Match the following 
 
4. Select the correct alternative  
(a) One litre is equal to : 
1.  1 cm
-3
 
2. 1 m
3
 
3.  10
-3  
cm
3
 
4. 10
-3
 m
3
 
(b) A metallic piece displaces water of volume 15 ml. The volume of piece is : 
1.  15 cm
3
 
2.  15 m
3
 
3.  15 × 10
3
 cm
3
 
4.  15 × 10
3
 cm
3
 
(c) A piece of paper of dimensions 1.5 m x 20 cm has area : 
1.  30 m2 
2.  300 cm2 
3.  0.3 m2 
4.  3000 m3 
(d) The correct relation is : 
1.  d = M × V 
2.  M = d × Y   
3.  V = d × M 
4.  d = M + V 
(e) The density of alcohol is 0.8 g cm-3. In S.I. unit, it will be : 
1.  0.8 kg m
-3
 
2.  0.0008 kg m
-3
 
3.  800 kg m
-3
 
4.  8 x 10
3
 kg m
-3
 
(f) The density of aluminium is 2.7 g cm-3 and of brass is 8.4 g cm
-3
. For the same 
mass, the volume of: 
1.  both will be same 
2.  aluminium will be less than that of brass 
3.  aluminium will be more than that of brass 
4.  nothing can be said. 
(g) A block of wood of density 0.8 g cm
-3
 has a volume of 60 cm
3
. The mass of block will 
be : 
1.  60.8 g 
2.  75 g 
3.  48 g 
4.  0.013 g 
(h) The correct relation for speed is 
1.  Speed = distance x time 
2.  speed = distance / time 
3.  speed = time / distance 
4.  speed = 1 / distance x time 
(i) A boy travels a distance 150 m in 1 minute. His speed is 
1.  150 m s
-1
 
2.  2.5 m s
-1
 
3.  25 m s
-1
 
4.  9 m s
-1
 
B. Short/Long Answer Questions 
Question 1. 
Define the term volume of an object. 
Answer: 
The space occupied by an object is called its volume. 
Question 2. 
State and define the S.I. unit of volume. 
Answer: 
S.I. unit of volume – The S.I. unit of volume is cubic metre. In short form, it is written as 
m
3
. 
One cubic metre is the volume of a cube of each side 1 metre as shown in figure below 
i.e., 1 m
3
 = 1 m × 1 m × 1 m. 
 
Question 3. 
State two smaller units of volume. How are they related to the S.I. unit? 
Answer: 
A smaller unit of volume is cubic centimetre (symbol cm
3
) and cubic decimetre (symbol 
1 dm
3
). One cubic centimetre is the volume of a cube of each side 1 centimetre, i.e., 
1 cm
3
 = 1 cm × 1 cm × 1 cm. 
Relationship between m
3
 and cm
3
  
l m
3 
= lm × lm × lm 
= 100 cm × 100 cm × 100 cm 
= 10,00,000 cm
3
 = 10
6
 cm
3
. 
Relationship between m
3
 and dm
3
 
l m
3
 = lm × 1 m × 1 m . 
= 10 dm × 10 dm × 10 dm 
= 1000 dm 
= 10
3
 dm 
Note 1 m = 10 dm