CBSE Class 9 - Biology - Why Do We Fall iLL? - Design Poster on Dengue (#cbseNotes)

Biology - Why Do We Fall ill? - Design Poster on Dengue

CBSE Class 9 - Physics - Gravitation - 51 Questions You must revise (#cbseNotes)

Gravitation - 51 Questions You must revise

Q1: What was geocentric model? Who proposed this theory?

Q2: What was heliocentric theory? Who proposed this?

Q3: If the mass of the body is 9.8 kg on the earth what would be its mass on the moon.

Q4: What are the Kepler Laws that govern the motion of the planets?

Q5(NCERT/CBSE 2010): State the universal law of gravitation.

Q6(NCERT): What is the importance of Universal Law of Gravitation?
      or
Q(CBSE 2010): State any one phenomena related to the Universal Law of Gravitation.


Q7(CBSE 2010): Why is G called the Universal Constant?


Q8: Who measured the value of G first time, experimentally?


Q9(CBSE 2010/NCERT): What is the gravitational force between the Earth and a body called? In which direction does it occur?

CBSE Class 9 - Biology - Tissues - Name the following (#cbseNotes)

Class 9 - Biology - Tissues
Name the following

Question. Name the following:

⒜ Tissue that forms the inner lining of our mouth

⒝ Tissue that transports food in plants

⒞ It provides buoyancy to lotus plant help it float.

⒟ Tissues present in lung alveoli

⒠ Connective Tissue with a fluid matrix

Class 9 - Biology - Tissues - 15 Amazing Facts About Blood That You Should Know (#cbseNotes)

15 Amazing Facts About Blood
That You Should Know

① Human heart pumps the blood 36 thousand liters of blood in the distance of 20 thousand kilometers in a day.

② Blood is a fluid connective tissue.

③ Human blood is red in colour due to the presence of red pigment i.e. haemoglobin.

☛You may download this blog post as a PDF File

④ The blood is always not red in all animals. The cockroach has white blood where as there is blue coloured blood in a snail.

CBSE Class 9 - Science - FORCE AND LAWS OF MOTION - Very Short Answer Questions You must Know (#cbseNotes)

FORCE AND LAWS OF MOTION

Class 9 - Physics

Very Short Answer Questions that you must know.


Q1: Give an example that force can make a stationary body move.

Answer: A football can be set to move by kicking it, i.e. by applying a force.



Q2: Name the scientist who experimented with moving balls on a ramp and proved that objects move with constant speed and when no force acts on them.

Answer: Galileo



Q3: Force can change the shape and size of an object. Give an example.

Answer: By hammering, a block of metal can be turned into a thin sheet. By hammering, a stone can be broken into pieces.



Q4: Why does a bicycle slow down when the cyclist stop pedalling? 

Answer: This is because of the frictional forces acting opposite to the direction of motion.



Q5: What are balanced forces?

Answer: If the resultant of applied forces is equal to zero, it is called balanced forces.

CBSE Class 9 - Science - Why Do We Fall iLL? - Infographic on Health (#cbseNotes)

Infographic on Health

Class 9 - Science 

Why Do We Fall iLL? 

See below the info graphic.

CBSE Class 11 / 9 - Physics - Gravitation - Understanding Mass and Weight (#cbseNotes)

Understanding Mass and Weight

Physics - Gravitation

Mass and Weight
The quantity of matter in a body is known as mass of the body. Mass is quantitative measure of inertia. Mass is an intrinsic property of matter and does not change as an object is moved from one location to another. Weight, in contrast, is the gravitational force that earth exerts on the object and can vary, depending on how far the object is above the earth's surface or whether it is located near another body such as the moon. The relation between weight W and mass m can be written in one of two ways:

W = GMₑm / r²
W = mg

According to the Newton's second law,
Force = mass ✕ acceleration

or mass = force / acceleration

Mass is of two types :
i) Inertial mass

ii) Gravitational mass


1. Inertial Mass:
Ratio of the applied external force and the acceleration produced in the body is known as inertial mass,

m_i = External force applied / Acceleration produced.

CBSE Class 9 - Force and Laws of Motion - What is Inertia? (#cbseNotes)

What is Inertia? 

CBSE Class 9 - Force and Laws of Motion 

Let's move the rock!

Inertia
It is inherent property of all bodies, by virtue of which it resists or opposes any change to it's present state of rest or of uniform motion. It varies directly as mass of the body.

Inertia of a body is of three types:

① Inertia of rest

It is in ability of a body to change by itself or if state of rest. This means a body at rest remains at rest and cannot start moving on its own.

CBSE Class 9 - Physics - Chapter - Force and Laws of Motion (Worksheet) (#cbseNotes)

Force and Laws of Motion
(Worksheet)

Q: Fill in the blanks with suitable choice given in brackets.

1: The product of mass and velocity of a body is called __________. (momentum/force)


2: The property by the virtue of which an object tends to remain in the state of rest or of uniform motion unless acted upon by some force is called __________. (impulse/ inertia)


3: The SI unit of _________ is kilogram meters per second i.e. kg m/s (momentum/ force)


4: Momentum is a _________ (scalar/ vector) quantity and is directed along the __________ (direction/ magnitude) of velocity.


5: The total momentum of the bullet and the gun before firing would be _________ (zero/ positive / negative) because both of them ar at rest.

CBSE Class 9 - Physics - Motion - Assignment Sheet (#cbseNotes)

Physics - Motion

Class-IX

Assignment Sheet

Q1(MCQs) : Choose the correct option from choices given.

ⅰ A particle is moving in a circular path of radius’ r’. The displacement after half a circle would be
(a) Zero
(b) π × r
(c) 2r
(d) 2 × π × r

ⅱ The numerical ratio of displacement and distance of a moving object is
(a) always greater than 1.
(b) always equal to 1.
(c) always more than 1.
(d) equal or less than 1.

ⅲ An object has moved through a finite distance
(a) its displacement must be equal to the distance moved by it.
(b) its displacement must be positive .
(c) its displacement is less than the distance moved by it.
(d) Displacement may be zero.

CBSE Class 9 - Science - Unit Test Paper (2017-18) (#cbsepapers)

CBSE Class 9 - Science Unit  Test Paper (2017-18)

Chapters Covered In Unit Paper:
   1. Straight Line Motion
   2. Cell - Fundamental Unit Of Life
   3. Matter and Its Surroundings

CBSE Class 9 - Chemistry - MATTER IN OUR SURROUNDINGS (Worksheet) (#cbsenotes)

MATTER IN OUR SURROUNDINGS 

Based on  Class 9 - Chemistry NCERT Chapter 

(Worksheet)

Fill in the blanks

① The process of converting solid into liquid is called _________.


② __________ is the process in which the liquid phase changes to gaseous phase at a constant temperature and constant pressure.


③ The amount of a water vapour present in air is called__________.


④ ________ is the reverse process of evaporation.

CBSE Class 9 - SA2 Science Sample Question Paper (2016-17)(#cbsepapers)

CBSE Class 9 - SA2 Science Sample Question Paper (2016-17)

CBSE Class 9 - SA2 Science Sample Question Paper (2016-17) Set-2 (#cbsepapers)

CBSE Class 9 - SA2 Science Sample Question Paper (2016-17) 

CBSE Class 9 - SA2 Science Sample Question Paper (2016-17)(#cbsepapers)

CBSE Class 9 - SA2 Science Sample Question Paper (2016-17)

CBSE Class 9 Chemistry - Questions based on Mole Concept (#cbsenotes)(#class9SA2Chemistry)

Questions Based on Mole Concept

CBSE Class 9 Chemistry

Q1: Fill in the blank.

The mole (mol) is the amount of a substance that contains as many elementary entities as there are atoms in exactly ________ of C₁₂


Answer: 12g or 12 grams.



Q2: I owe you 1 mole of rupees. How many rupees do I have to pay for you?


Answer: 6.022 × 10²³ rupees.


Q3: Is mole a unit?

Answer: No, it is a large constant number called Avagadro's constant (N) = 6.022 × 10²³


Q4: Atomic mass of Na is 23u. What is the mass of 1 mole of Na atoms? Is there any name for this?

Answer: 23g. It is also called the molar mass of Na atoms.



Q5: Atomic mass of oxygen(O) is 16u. What's its molar mass?

Answer: 16g.



Q6: What is the molecular mass of Water molecule (H₂O)?

Answer: Atomic mass of H = 1u
The atomic mass of O = 16u

The molecular mass of H₂O = mass of 2 atoms of H + mass of 1 atom of O
= 2 × 1u + 16u
= 18u



Q7: What is the molar or gram molecular mass of water?

Answer: Molecular mass of Water (H₂O) = 18u
Gram molecular mass = 18g or 18 grams



Q8: How many moles will be in 45g of water(H₂O)?

Answer: Molecular mass of H₂O = 18u
Mass of 1 mole of H₂O = 18g
No. of moles in 45g of H₂O = 45 ÷ 18 = 2.5 moles



Q9: How many atoms of Hydrogen are there in 2 moles of water?

Answer: 1 molecule of H₂O has H-atoms = 2 atoms
1 mole of H₂O has H-atoms = 2-mole atoms
2 moles of H₂O has H-atoms = 2 × 2 = 4 moles of atoms
= 4 × 6.022 × 10²³
= 24.088 × 10²³
= 2.4088 × 10²⁴ H-atoms


Q10: How many grams of SiO₂ are present in 0.8 mol? (molecular mass of SiO₂ = 60.1u)

Answer: Molecular mass of SiO₂ = 60.1u
1 mole of SiO₂ = 60.1g
0.8 mol of SiO₂ = 60.1 × 0.8 = 48.1g



Q11: Under standard temperature pressure conditions, what is the volume of 1 mol of gas?

Answer: 22.4 litres or 22.4l


Q12: How many mol of CO₂ (carbon dioxide) are present in 55.5 L ?

Answer: 1 mol of CO₂ = 22.4 l
55.5 litres contains = 55.5/22.4
= 2.48 mol of CO₂


Q13: What will be the mass of 12.044 × 10²³ molecules of O₂?

Answer: Molecular mass of O₂ = 2 × 16u = 32u
∴ 1 mol of O₂ = 32g
⇒ 6.022 × 10²³ O₂ molecules have mass = 32g
  12.044 × 10²³ molecules of O₂ = 32 × 12.044 × 10²³ / (6.022 × 10²³)
  = 32 × 2
  = 64g


Q14: Calculate the mass of glucose in 2 × 10²⁴ molecules. Molecular mass glucouse is 180u

Answer: Molecular mass of glucouse = 180u
Gram molecular mass of glucouse = 180g
⇒ 1 mole (6.022 × 10²³) molecules = 180g
2 × 10²⁴ molecules will have mass = 180 × 2 × 10²⁴ / (6.022 × 10²³)
= 180 × 2 × 10 / 6.022 = 597.7 g


Q15: Write formula to calculate Number of moles 

(a) of monoatomic substance, if its mass is given
(b) of a molecular substance, if its mass is given
(c) of a monoatomic substance, if number of atoms are given
(d) of a molecular substance, if number of molecules are given


Answer:
(a)

No. of moles =	mass
	atomic mass

(b)

No. of moles =	mass
	molecular mass

(c)

No. of moles =	no. of atoms
	6.022 × 10²³

(d)

No. of moles =	no. of molecules
	6.022 × 10²³

CBSE Class 9 - Science Pre-SA2 Sample Question Paper (2016-17) (#cbsepapers)

CBSE Class 9  - Science Pre-SA2 Sample Question Paper (2016-17)

CBSE Class 9 -Science - Natural resources (Worksheet - Important Terms) (#cbseClass9Notes)

Natural Resources

Worksheet 

Important Terms

☛Following are the statements that define specific terms related to Natural resources. Identify the terms and fill in the blanks.


1. The outer crust of the Earth.

______________


2. The region which includes all the earth's liquid water, frozen water and small amounts of water vapor in the earth's atmosphere.

_____________________


3. The mass of air surrounding the Earth.

_____________________


4. The life-supporting zone of the Earth where the atmosphere, hydrosphere and lithosphere interact and make life possible.

_____________________

CBSE Class 9 - Science - Structure Of Atom (Question Bank) (#CBSENotes) (#CBSEClass9Science)

Structure Of Atom

(Question Bank)

Questions Based on Class 9 NCERT Science Chapter

Q.1: Define atomic number.

Q.2: What is an electron? Who discovered it?

Q.3: Name the particles which determine the mass of an atom.

Q.4: Study the composition of the two nuclei of two atomic species L and M
L = protons 20, neutrons 20
M = protons 18, neutrons 22
Give the relation between the two.

Q.5: Write the formula for calculating the maximum number of electrons in an orbit.

Q.6: Name the particles that have no charge and their mass is equal to that of proton. Who discovered these particles?

Q.7: What is charge/mass ratio of an electron?

Q.8: What is the valency of oxygen [Atomic number of oxygen=8]?

Q.9: Write the notation of an atom ‘X’, if the mass number is A and the atomic number is Z.

Class 9 - Science - SOUND - Question Bank (#CBSENotes) (#CBSEClass9Notes)

SOUND

Question Bank

Question Bank based NCERT Class 9 Science Chapter on Sound.
Following questions have been asked in previous CBSE examination papers.


Q 1: Define frequency of a wave.

Q 2: Give a relation correlating sound velocity with its frequency and wavelength.

Q 3: What is SI unit of frequency?

Q 4: What is the true meaning of amplitude of a longitudinal wave?

Q 5: How is frequency of a wave related to its time period?

Q 6: On what factors does the loudness of a sound depend?

Q 7: Which sound has higher energy, a loud sound or a soft sound?

Q 8: On what factors does speed of sound in a medium depend?

Q 9: Define echo.