Matric Part 1/9th Class Physics Chapter 7 Long Question With Answer for Unit 7 Properties of Matter

Question # 1

Q no: 7B) State Archimedes principle and prove it and derive equation of up thrust of liquid.

Ans 1: Archimedes Principle:
When is totally or partially immersed in a liquid, an up thrust act on it equal to the weight of the liquid it displaces.
Explanation:
Consider a solid cylinder of cross-sectional area A and height h immersed in a liquid. Let h1 and h2 be the depth of the top and bottom surfaces of the liquid.
Then
h2-h1= h
If P1 and p2 are the pressures at the depth h1 and h2 p is its density, then
P1= pgh2
P2= fgh2
Let the force F1 is exerted the cylinder top by the liquid due to pressure P1 and the force F2 is exerted at the bottom of the cylinder due to P2
So
F1=pgh1A
F2=pgh2A
F1 and F2 are acting on the opposite faces of the cylinder. Therefore, the net force F will be F2- F1 in the direction of F2
F2 - F1 = pgh2A -pgh1A
=pgA(h2-h1)
=pghA
= pgV

Question # 2

Q no: 5 (A) Derive the formula of Young Modulus.?

Ans 1: Young's Modulus:
The ratio of stress and strain is a constant within the elastic limit , this constant is called the young's Modulus.
Mathematical Form:
Consider a long bar of length L_o and cross- sectional area A let an external force F is equal to weight stretches it such that the stretched length becomes L.
Mathematically.
Young's Modulus = Y = Stress/Tensile strain
Let ▲L =L-L_o
Since-
Stress = Force/Area =F/A
And
Tensile strain = L-L_o/L_o= ▲L/L_o
As
Young's modulus = Y = Stress/Tensile strain
=F/A x L_o/▲L
= F x L_o/A x▲L

Question # 3

State and explain Young's modulus.

Ans 1: Young' modulus; the ratio of stress to tensile strain is called young's modulus.
Ans 2: Explanation; consider a long bar of length l and cross sectional area A. Let an external force F equal to the weight stretches it such that the stretched length become L. According to Hook's law, the ratio of the stress to tensile strain is constant within the elastic limit of the body.

Question # 4

Explain breaking system in vehicles

Ans 1: Breaking system in vehicles: the braking system of cars, buses , etc. also work on Pascals law. The hydraulic breaks allow equal pressure to be transmitted throughout the liquid. When break pedal is pushed, it exerts a force on the master cylinder, which increases the liquid pressure in it. The liquid pressure is transmitted equally through the liquid in the metal pipes to all the pistons of other cylinder s. Due to the increase in liquid pressure, the piston in the cylinders move outward pressings the break pads with the brake drums. The force of friction between the brake pads and the brake drums stops the wheels.

Question # 5

What are the features of kinetic molecular model of matter? explain the types of matter

Ans 1: Kinetic molecular model: the features of kinetic molecular model of matter is following
1. Matter is made up of particles called molecules
2. The molecules remain in continuous motion
3. Molecules attract each other
Ans 2: Types of matter: the types of matter are following
Solid: solid are very hard . They have fixed shapes and volume. Their molecules are held close together by strong forces of attraction. The vibrate about their mean positions but don not move from place to place.
Example: their examples are stone, metal spoon , pencil etc.
Ans 3: Liquids; the distances between the molecules of a liquid are more than in solids. Thus, attraction forces between them are weaker. They have fixed volume and boiling point. Viscosity and fluidity present in liquids. Their shapes change w.r.t container.
Example: their examples are water, milk , drinks etc
Ans 4: Gases; gases have no fixed shaped and volume. They can be filled in any container of any shape. Their molecules have random motion and high velocities. In gases, molecules are much farther apart than solids or liquids. Gases are lighter than solids and liquids.
Example: their examples are hydrogen, helium, neon, nitrogen etc.
Ans 5: Plasma: when heat is provided to any matter their kinetic energy of molecules increases. They collide to each other , by this collision thy lose their electrons and become positive ions. The mixture of ions, atoms and molecules is called plasma. It is the fourth state of matter. positive ions an electrons get separated in the presence of electric and magnetic fields . It is highly conduction state of matter. it allows electric current to pass through it.
Origin and uses; the most part of the universe is made of plasma. Sun is made of plasma. It exists in neo and fluorescent tubes when they glow.

Question # 6

Q no 5 (B) How much would be the volume of ice formed by freezing 1 liter of water.

Ans 1: Data:
Volume of water = V₁= 1 liter Volume of ice on freezing=V₂= ?
Solution:
As we know that Volume of ice/Volume of water =density of water/density of ice
Volume of ice = density of water/density of ice x Volume of water
= 1000/920 x 1
= 109 liters Ans

Question # 7

Q no 6B) Thedensity of air is 1.3 Find the mass of air in measuring 8m x 5m x 4m.

Ans 1: Data:
= 1.3
v= 8m x 5m x 4m
= 160m³
m = ?
Solution:
As we know that
Density = Mass/Volume
Mass = Density x Volume
=1.3 x 160
m = 208kg Ans

Question # 8

Define pressure. explain it with examples

Ans 1: Pressure; the force acting normally per unit area on the surface of a body is called pressure.
unit: its S.I unit is Nm-2 or pascal(Pa). Thus 1 Nm-2 =1Pa
Dependence; it depends upon area and applied force
Ans 2: Examples;
1. press a pencil from its ends between the palms. The palm pressing the tip feels much more pain than the palm pressing its blunt end.
2. we can push a drawing pin into a wooden board by pressing it by out thumb. It is because the force we apply on the drawing pin is confined just at a very small area under its sharp tip. A drawing pin with a blunt tip would be very difficult to push into the board due to the large area of its tip.

Question # 9

Define elasticity. explain deforming force, stress, strain and tensile strain.

Ans 1: Elasticity: the property of a body to restore its original shape and size as the deformation force ceases to act is called elasticity.
Ans 2: Deforming force; the applied force that changes shape , length or volume of a substance is called deforming force. In most of the case s, the body returns to its original size and shaper as soon as the deforming force is removed.
Ans 3: Stress: the force acting on a unit area at the surface of a body is called stress
Unit: the S.I unit of stress is newton per square meter(Nm^-2).
It is a scalper quantity
Ans 4: Strain: the ratio between change in object and original object is known as strain. When stress acts on a body, it may change its length , volume, or shape.
Unit: it has no unit due to ration between similar quantities.
Ans 5: Tensile strain: when stress produces a change in the length of an object then the strain is called tensile strain.
Unit: it has no unit as it is simply a ration between two similar quantities.

Question # 10

Explain the variation in atmospheric pressure

Ans 1: Variation in atmospheric pressure : the atmospheric pressure decrease as we go up. The atmospheric pressure on mountain's is lower than at sea level. At a height above 30km, the atmospheric pressure becomes only7mm of mercury which is approximately 1000pa. It would becomes zero at an attitude where there is no air. Nearly half of its mass is between sea level and 10km. up to 30 km from sea level contains about 99% of the mass of the atmosphere. Thus, we can determine the altitude of a place by knowing the atmospheric pressure at that place.
Atmospheric pressure may also indicate a change in the weather . On a hot day, air above the earth becomes hot and expands. This causes a fall of atmospheric pressure in that region. On the other hand, during cold chilly nights, air above the earth cool down. This causes an increase in atmospheric pressure.
The changes in atmospheric pressure at a certain place indicate the expected changes in the weather condition of the place . For example, a gradual and average drop in atmospheric pressure means a low pressure in neighboring locality. Minor but rapid fall in atmospheric pressure indicates a windy and showery condition in nearby region. A decrease in atmospheric pressure is accompanied by breeze and rain. Whereas a sudden fall in atmospheric pressure often followed by a storm, rain and typhoon to occur in few hour time.
On the other hand, an increasing atmospheric pressure with a decline later on predicts an intense weather conditions. A gradual large increase in the atmospheric pressure indicates a long spell of pleasant weather .condition. A rapid increase in atmospheric pressure means that it will soon be followed by a decrease in atmospheric pressure indicating poor weather ahead.

Latest Educational News Stories

Pakistan's Largest Database of Colleges and Universities

BS Programs

University Past Papers

University Results

Exam Results 2024

Study Abroad Programs and Opportunities for Pakistani Students

Matric Part 1/9th Class Physics Chapter 7 Long Question With Answer for Unit 7 Properties of Matter

9th Class English Medium Subjects

9th Class Urdu Medium Subjects

Online Long Questions For Chapter 7 "9th Class Physics Chapter 7 Long Question Preparation "

Physics (New Book) - 9th Class Physics Chapter 7 Long Question Preparation

Q no: 7B) State Archimedes principle and prove it and derive equation of up thrust of liquid.

Q no: 5 (A) Derive the formula of Young Modulus.?

State and explain Young's modulus.

Explain breaking system in vehicles

What are the features of kinetic molecular model of matter? explain the types of matter

Q no 5 (B) How much would be the volume of ice formed by freezing 1 liter of water.

Q no 6B) Thedensity of air is 1.3 Find the mass of air in measuring 8m x 5m x 4m.

Define pressure. explain it with examples

Define elasticity. explain deforming force, stress, strain and tensile strain.

Explain the variation in atmospheric pressure

Prepare Complete Set Wise Questions For Chapter 7 "9th Class Physics Chapter 7 Long Question Preparation "

Set 1

Set 2

9th Class Physics Chapter 7 Long Question Preparation - Set 1

Q no: 7B) State Archimedes principle and prove it and derive equation of up thrust of liquid.

Q no: 5 (A) Derive the formula of Young Modulus.?

State and explain Young's modulus.

Explain breaking system in vehicles

What are the features of kinetic molecular model of matter? explain the types of matter

Q no 5 (B) How much would be the volume of ice formed by freezing 1 liter of water.

Q no 6B) Thedensity of air is 1.3 Find the mass of air in measuring 8m x 5m x 4m.

Define pressure. explain it with examples

Define elasticity. explain deforming force, stress, strain and tensile strain.

Explain the variation in atmospheric pressure

9th Class Physics Chapter 7 Long Question Preparation - Set 2

State and explain Pascals law

Q no: 5 (A) Derive the formula of Young Modulus.?

State and explain Hook's law

What is barometer? how atmospheric pressure is measured using a barometer

Define atmospheric pressure . explain it

Q no 5 (B) How much would be the volume of ice formed by freezing 1 liter of water.

What is density? explain

Explain breaking system in vehicles

Explain how submarine moves up the water surface down into water

Q no:6 (A) State the Pascal's law. What are its applications in our daily life?

9th class Physics Chapter 7 Long Q's (English Medium)

Share your comments & questions here