Showing posts with label class8-science. Show all posts
Showing posts with label class8-science. Show all posts

Friday, 5 October 2018

Class 8 - Science - Combustion and Flame - Study Points (#cbsenotes)(#eduvictors)

CBSE Class 08 Science 
Study Points

Chapter 6: Combustion and Flame

Class 8 - Science - Combustion and Flame - Study Points  (#cbsenotes)(#eduvictors)

Combustion: The process of burning a substance in the presence of air (oxygen) and undergoes a chemical reaction to produce heat and light.

The substances which burn in the air are called combustible.

Oxygen (in air) is essential for combustion.

During the process of combustion, heat and light are given out.

Ignition temperature is the lowest temperature at which a combustible substance catches fire.

Types of combustion: The type of combustion differs depending on the type of fuel. Based on nature and intensity, combustions are classified into three types. They are:
        (i) Rapid combustion
        (ii) Spontaneous combustion
        (iii) Explosion

The calorific value of a fuel is expressed in kilojoules per kilogram (kJ/kg).

Wednesday, 5 September 2018

CBSE Class 10 - Biology - Reproduction in Plants - Very Short Questions Answers (#cbsenotes)(#eduvictors)

Reproduction in Plants 

Class 10 Biology

Stamen, Anthers: Credits: Sandeep Handa


Very Short Questions Answers


Q1: Write two ways in which pollination may occur in plants.

Answer: The two ways in which pollination may occur in plants are:
Self-pollination.
Cross-pollination.


Q2: Name the three agents of pollination.

Answer: The three agents of pollination are:
Insect
Wind
Water


Q3: Name any three agencies for dispersal of seeds.

Answer:
Wind
Water
Man and animals, birds, bats, squirrels.


Friday, 17 August 2018

CBSE Class 8 - Science - Synthetic Fibres and Plastics (MCQs) - NCERT Exemplar Answers (#cbsenotes)(#eduvictors)

Synthetic Fibres and Plastics


Multiple Choice Questions

Question 1: Pick the synthetic fibre out of the following.

(a) Cotton
(b) Nylon
(c) Jute
(d) Wool


Question 2: Which of the following is a source of rayon?

(a) Wool
(b) PET
(c) Wood pulp
(d) Silk


Question 3: Polycot is obtained by mixing

(a) nylon and wool
(b) polyester and wool
(c) nylon and cotton
(d) polyester and cotton


Wednesday, 25 July 2018

NCERT Class 8 - Science - Chapter: Force and Pressure (Worksheet) (#cbsenotes)(#eduvictors)

Force and Pressure 

Class 8 - Science
(Worksheet)

NCERT Class 8 - Science - Chapter: Force and Pressure (Worksheet) (#cbsenotes)(#eduvictors)


Fill in the blanks

1. Muscular force is an example of _______ force.

2. Oil is applied to machines to reduce _______ force.

3. S.I unit of pressure is ____________.

4. S.I. unit of force is _____________.

5. If the area of contact is increased, then pressure ______ _.

6. Pressure in solid depends upon ________________ and ____________.

Monday, 16 July 2018

Class 6/7/8/9/10 Entrance Tests/NTSE/CTET/NDA - General Science Quiz (2018) (#eduvictors)

General Science Quiz 

Class 6/7/8/9/10 Entrance Tests/NTSE/CTET/NDA - General Science Quiz (2018) (#eduvictors)

Q1: Which of the following is not example bio-mass energy source?

(a) Wood
(b) Gobar gas
(c) Atomic energy
(d) Coal


Q2: The scientific study of earthquakes is known as 

(a) Seismology
(b) Cosmology
(c) Ecology
(d) Pathology


Q3: Which of the following is a plant hormone?

(a) Insulin
(b) Thyroxin
(c) Estrogen
(d) Cytokinin


Monday, 11 June 2018

CBSE Class 8 - Science - Microorganisms - Friends Or Foes (Questions and Answers) (#cbsenotes)(#eduvictors)

Microorganisms – Friends or Foes (Q & A-2)

Class 8 – Science – Microorganisms – Friends or Foes (Worksheet) (#cbseNotes)

Q1: Fill in the blanks:
a. Microorganisms may be unicellular or ___________.

b. __________ bacteria help to make curd from milk.

c. Disease-causing microorganisms are called _______.

d. Ammonium salt in the soil is converted first into nitrites by _________ bacteria.

e. _______ coagulation takes place only when milk is hot.

f. Salting draws out _______ from food.

g. Nitrate in the soil is converted by _________ bacteria into nitrogen gas.

h. The process of preventing food spoilage by chemical or physical methods is called food ________.

Answer:
a. Multicellular
b. Lactobacillus
c. pathogens
d. Nitrifying
e. Casein
f. water
g. denitrifying
h. preservation

Monday, 9 April 2018

CBSE Class 8 - Science - Friction (Worksheet) (#cbsenotes)(#eduvictors)

Science - Friction (Worksheet)

CBSE Class 8 - Science - Friction (Worksheet) (#cbsenotes)(#eduvictors)

MCQs (1-10)

Q1. It is difficult to walk on any oily floor because

a) Floor gets spoiled
b) There is more resistance
c) Force of friction is high
d) Force of friction is very less


Q2: Spring balance is a device used for measuring the _____________ acting on an object.

a) mass
b) pressure
c) force
d) None of the above


Q3: A matchstick struck on a matchbox catches fire easily because

a) Friction may cause a fire
b) Of chemical reaction
c) Force heated the matchstick
d) None of the above

Sunday, 1 April 2018

Class 7/8/10 - Forests Our Life Line or Natural Resources - Importance of Forest Resources (#cbsenotes)(#eduvictors)

Natural Resources - Importance of Forest Resources

Class 7/8/10 - Forests Our Life Line or Natural Resources - Importance of Forest Resources (#cbsenotes)(#eduvictors)

The importance of forest resources can be described  as follows:

1. Ecological Balance
2. Renewable Natural Resources
3. Eco-system
4. Economic Development
5. Environment Quality
6. Safeguard against Pollution
7. Soil Conservation
8. Wind and Soil Erosion
9. Check the Extension Balance
10. Maintains Ecological Balance
11. Attracts Rainfall
12. Control Floods
13. Connects to our Cultural and Civilization
14. Supply of Raw Material


1. Ecological Balance: 

Forests and wildlife are essential to maintain ecological balance of an area.


Saturday, 31 March 2018

CBSE CLASS 8 - Science - Crop Production and Management (50+ Very Short Question and Answers) (#eduvictors)(#cbsenotes)

Crop Production and Management (50+ Very Short Question and Answers)


CBSE CLASS 8 - Science - Crop Production and Management (50+ Very Short Question and Answers) (#eduvictors)(#cbsenotes)


Q1: Define agriculture.

Answer: Cultivation of plants and rearing of animals for food and other beneficial items is called agriculture.


Q2: Where do animals get their food?

Answer: Animals get their food by eating other animals or plants.


Q3: What do you mean by crop?

Answer: Plants which are of the same kind and grown and cultivated at a place in large quantities are known as the crop.


Q4: Name two broad cropping patterns.

Answer: 1. Kharif crops
               2. Rabi crops


Q5: Give two examples of Kharif crops.

Answer: 1. Paddy  2. Maize


Q6: Give two examples of Rabi crops.

Answer: 1. Wheat  2. Gram


Q7: Define agricultural practices?

Answer: Various steps followed in growing crops and storing the crop grains is known as agricultural practices.


Q8: Define the term tilling or ploughing.

Answer: Tilling or Ploughing is the process of loosening and turning of the soil.


Q9: What is plough?

Answer: The device used for ploughing is called plough.


Q10: Name any two materials used to make a plough.

Answer: Wood and iron are used to make a plough.

Monday, 1 January 2018

CBSE Class 8 - Science Chapter - Light (Unit Test) (#cbseNotes)(#eduvictors)

Light (Unit Test Paper)

CBSE Class 8 - Science Chapter - Light (Unit Test) (#cbseNotes)(#eduvictors)

Time: 1½ Hrs

Q1: If the angle between the mirror and the incident ray is 30°, what is value of the angle of reflection?

Q2(MCQ): Two plane mirrors are kept at the following angles one by one. In which case is the number of images formed the maximum?
a. 30° b. 60° c. 45° d. 90°

Note: (Q3 – Q8) Give One Word Answer

Q3: Is the reflection of light by the smooth walls of your house regular or irregular?

Q4: A plane mirror always forms the image of an object exactly on the reflecting surface. True or false?

Q5: Is the image formed by a plane mirror exactly of the same size as the object?

Friday, 22 December 2017

Class 7/8/9/10 - Science - Clean Air: From Donora to Delhi - Can we breathe safely? (#eduvictors)(#cbse-notes)

Clean Air: From Donora to Delhi -
Can we breathe safely?

Class 7/8/9/10 - Science - Clean Air: From Donora to Delhi - Can we breathe safely? (#eduvictors)(#cbse-notes)

With the industrial revolution, the human mankind experienced the air pollution for the first time and realized it as a potential threat to human life. The black smoke of locomotives, factories from the industrial towns of England blackened its cities.

In 1950s, the smoke of industrialized Pennsylvania valley in USA made the air murkier. In the small town of Donora, population 14,000, residents suffered eye, nose, and throat irritation and breathing difficulties resulting in 20 deaths.

In 2008, on the 60th anniversary of the event, the town opened the Donora Smog Museum with the
slogan "Clean Air Starts Here".

Wednesday, 29 November 2017

CBSE CLASS 8 - SCIENCE - CHEMICAL EFFECTS OF ELECTRIC CURRENT (WORKSHEET) (#eduvictors)(#cbseNotes)

CHEMICAL EFFECTS OF ELECTRIC CURRENT (WORKSHEET)

CBSE CLASS 8 - SCIENCE - CHEMICAL EFFECTS OF ELECTRIC CURRENT (WORKSHEET) (#eduvictors)(#cbseNotes)


Here a few definitions are written. Identify the term these sentences define.


1. A substance which gives ions when melted or dissolved in water is called a/an __________.


2. Sodium Hydroxide, common salt, sulphuric acid are examples of ___________.


3. Sugar, Urea, Benzene Ethyl alcohol are examples of ____________.


4. Materials which allow electricity to pass through them are called __________.


5. Metals are generally _________ of electricity.

Sunday, 5 November 2017

CBSE Class 8 Science – Light, Refraction and Dispersion - Assignment (#cbseNotes) (#eduvictors)

CBSE Class 8 Science – Light, Refraction and Dispersion - Assignment (#cbseNotes) (#eduvictors)

Science – Light, Refraction and Dispersion - Assignment


Q1: What do you mean by refraction of light? In which direction will light bend when travelling from an optically rarer medium to an optically denser medium?

Q2: Name the part of the eye which gives colour to the eyes.

Q3: Boojho while waving his hand very fast in front of his eyes, observes that his fingers appear blurred. What could be the reason for it?

Q4: How many times is a ray of light reflected by two plane mirrors placed parallel and facing each other?

Saturday, 28 October 2017

CBSE Class 8 Science - Chemical Effects of Electric Current (Q and A) (#cbseNotes)

Chemical Effects of Electric Current (Q and A)

CBSE Class 8 Science - Chemical Effects of Electric Current (Q and A) (#cbseNotes)

Q1: Which of the following liquids conduct electricity & which do not conduct electricity?
Lemon juice, Milk, Vinegar, Salt solution, Distilled water, Honey, Seawater, Rainwater.

Answer:
Conducting: Lemon juice, Vinegar, Salt solution, sea water, Rainwater
Non-Conducting: Milk, Distilled water, Honey.


Q2: What is an electric current?

Answer: The rate of the flow of charge is called an electric current.


Q3: Name a device which glows even when a weak electric current passes through it.

Answer: LED (Light Emitting Diode)


Friday, 6 October 2017

CBSE Class 8 - Science - Ch 8 - Cell Structure and Functions (Worksheet) (#cbseNotes)


Cell Structure and Functions (Worksheet) 


CBSE Class 8 - Science - Ch 8 - Cell Structure and Functions (Worksheet) (#cbseNotes)


Fill in the blanks

1. ______ is the structural and functional unit of life.


2. All living organisms are made of ______.


3. Cells were first observed by ____________ in 1665.


4. Antonie van Leeuwen hook was the first to see __________ under microscope which he had constructed himself

Saturday, 30 September 2017

CBSE Class 8 Science - Term 1 - Sample Question Paper (2017-18) (#cbsePapers)

SAMPLE PAPER OF SCIENCE FOR Term-1 (2017-18)       

CLASS-VIII
CBSE Class 8 Science - Term 1 - Sample Question Paper (2017-18) (#cbsePapers)
M.M-90                                                                                                              Time: 3 Hrs

General Instructions:
1. The question paper consists of 34 questions and is divided into four sections, A, B, C and D
2. All questions are compulsory.
3. Section A comprises question numbers 1 to 10. Each carries 1 mark
4. Section B comprises question numbers 11 to 20. Each carries 2 marks
5. Section C comprises question numbers 21 to 30. Each carries 3 marks.
6. Section D comprises question numbers 31 to 34. Each carries 5 marks.

SECTION-A  
Q1. Name the process of sowing seeds by scattering them in the field by hand.
Q2. Why are dried neem leaves put in the container in which food grains are stored?
Q3. What is the huge reserve stock of food grains held by government agencies called?
Q4. How is yeast a beneficial fungi?
Q5. Which antibiotic was discovered first and who discovered it?
Q6. Which phenomenon  disturbs the nitrogen cycle?
Q7. Are the handles and bristles of tooth brush made of same material?
Q8. Why are metals used to make bells and musical instruments?
Q9. How does pressure at a point within a liquid change with its depth?
Q10. Why  is a sharp knife more effective in cutting a fruit than a blunt life?

Friday, 29 September 2017

CBSE Class 8 - Science - Ch 18 Pollution Of Air and Water - Chapter Notes (#cbseNotes)

POLLUTION OF AIR AND WATER

(Chapter Notes)
CBSE Class 8 - Science - Ch 18 Pollution Of Air and Water - Chapter Notes (#cbseNotes)

Pollution is release of harmful substances in the environment thus causing threats to our ecosystem. Even non-harmful substances when precipitated in environment can be harmful. Land, water and air are the most important natural resources. Man made factors (agriculture, industrialization, transport etc.) are the primary reasons for the pollution.

According to World Health Organizations, five millions deaths occur in India due to pollution.
Pollution can be classified in many categories like:
  • Land Pollution
  • Air Pollution
  • Water Pollution
  • Noise Pollution
  • Light Pollution
Here we discuss primarily about Air pollution and Water pollution.
Composition of Air
Air is a mixture of gases. 
By volume, Nitrogen:78%, Oxygen:21% and 1% (remaining gases like Carbon Di-oxide, Ozone, Argon, Methane etc.)