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

Question # 1

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 # 2

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

Ans 1: Barometer; the instrument that measure atmospheric pressure is called barometer.
Ans 2: Construction of barometer; one of the simplest barometer is mercury barometer . It consists of a glass tube 1 m long closed at one end. It is filled with mercury
Ans 3: measurement of atmospheric pressure using a barometer : to measure atmospheric pressure, then after filing with mercury, barometer is invented in a mercury trough. Mercury in the tube descends and stops at a certain height. The column of mercury held in tube exerts pressure at its base. At sea level the height of mercury column above the mercury in the trough is found to be about 76 cm . Pressure exerted by 76 cm of mercury column is nearly 101300Nm-2 , equal to atmospheric pressure . It is common to express atmospheric pressure in term of height of mercury column. As the atmospheric pressure at a place does not remains constant, hence the height of mercury column also varies with atmospheric pressure .

Question # 3

Q no: 7 (A) Explain hydraulic press, on what principle does it work.

Ans 1: Data :
F= 20N
L= 10mm
= 10 x 10^-3m
A= L x L = 10 x 10^-3x 10 x 10^-3
= 100 x 10^-6
= 1 x 10^-4m²
p=?
Solution:
As we know that
P = F/A
P= 20/1 x 10^-4
P= 20 x 10⁴
P= 2 x 10⁵Nm^-2 Ans

Question # 4

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 # 5

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 # 6

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

Ans 1: Pascal's Law:
Pressure applied at any point of liquid anclosedin a containeris transmitted without the loss to all other parts of the liquid.
An external force applied on the surface of a liquid increases the liquid pressure at the surface of the liquid. This increase in liquid pressure is transmitted equally to all direction and to the walls of the container in which it is filled.
Applications of Pascal's Law:
Hydraulic press is a machine which works on the principle which works on the principle of Pascal's law. It consists of two cylinders which are fitted with pistons of cross-sectional area a and A. The object is to be compressed is placed over the pistonof large cross- sectional areea A. The force is applied on the piston of cross-sectional area a.

The pressure P produced by small piston is transmitted through the liquid and acts on the large piston and a force F₂ acts on
A Which is much larger than F₁.

Question # 7

What is density? explain

Ans 1: Density; density of a substance is defined as its mass per unit volume
Unit: its S.I unit is kilogram per cubic meter (kgm^-3)
Ans 2: Explanation; if we take equal volume of iron and wood, then we can easily declare that iron is heavier than wood. it means that density of iron is heavier than wood

Question # 8

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 # 9

How we can find the density of an object

Ans 1: Density of an object: Archimededs principle is also helpful to determine the density of an object. The ration in the weight of a body wiht an equal volume of liquid is the same as in theri densitites.
Density of object = D
Density of liquid= p
Weight of object = w1
Weight of equal volume of liquid = w= w1-w2
here w2 is the weight of the solid in liquid. According to archimedes principle, w2 is less than its actual weight w1 by an amount w.

Question # 10

Define atmospheric pressure . explain it

Ans 1: Atmospheric pressure ; the earth is surrounded by a covered of air called atmosphere. It extends to a few hundred kilometer above sea level. Air is mixture of gases. The density o air in the atmosphere is not uniform. It decrease s continuously as we go up. It acts in all directions
Ans 2: Experiment; take an empty tin can with a lid. Open its cap and put some water in it. Place it over flame. Wait till water begins to boil and the steam expels the air out of the can. Remove it form the flame. Close the can firmly by its cap. Now place the can under tap water. The can will squeeze due to atmospheric pressure.
When the can is cooled by tap water, the steam is it condenses. As the steam changes into water, it leaves an empty space behind it. This lower the pressure inside the can as compared to the atmospheric pressure outside the can. This will cause the can to collapse from all directions. This experiment shows hat atmosphere exerts pressure in all directions. The fact can also be demonstrated by collapsing of an empty plastic bottle when air is sucked out of it.

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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

Define pressure. explain it with examples

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

Q no: 7 (A) Explain hydraulic press, on what principle does it work.

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

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

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

What is density? explain

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

How we can find the density of an object

Define atmospheric pressure . explain it

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

Define pressure. explain it with examples

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

Q no: 7 (A) Explain hydraulic press, on what principle does it work.

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

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

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

What is density? explain

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

How we can find the density of an object

Define atmospheric pressure . explain it

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

How we can find the density of an object

Define pressure. explain it with examples

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

Explain the application of atmospheric pressure in daily life

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

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

Explain the variation in atmospheric pressure

Define atmospheric pressure . explain it

What is density? explain

Explain how submarine moves up the water surface down into water

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

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