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Showing posts with label class9-science. Show all posts
Showing posts with label class9-science. Show all posts
Wednesday 13 September 2017
Tuesday 12 September 2017
CBSE Class 9 - Physics - Gravitation (Worksheet) (#cbseNotes)
Physics - Gravitation (Worksheet)
Fill in the blanks:
1. Motion of body with constant speed in a circular path is called ______________.
2. The acceleration which causes changes only in direction of the velocity of a body is called __________ and it is always directed ___________ the circle.
3. Every object in the universe ________ other bodies.
4. A body is said to be in _______ when only gravity acts on it.
5. ________ of an object is the force of gravity acting on it.
Monday 4 September 2017
Friday 1 September 2017
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?
Thursday 31 August 2017
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
Sunday 20 August 2017
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.
Friday 4 August 2017
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
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.
Thursday 3 August 2017
Saturday 15 July 2017
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,
mi = External force applied / Acceleration produced.
Wednesday 12 July 2017
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.Friday 16 June 2017
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.
Thursday 11 May 2017
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.
Friday 28 April 2017
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
Friday 24 March 2017
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.
Tuesday 21 March 2017
Thursday 16 March 2017
Sunday 12 March 2017
Sunday 26 February 2017
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 |
Tuesday 14 February 2017
Thursday 2 February 2017
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.
_____________________
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