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

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.)

Wednesday 20 September 2017

CBSE Class 8 - Science - Solar System Some Facts (#cbseNotes)

Solar System (Some Facts)

CBSE Class 8 - Science - Solar System Some Facts (#cbseNotes)


• Biggest Planet : Jupiter

• Smallest Planet : Mercury

• Nearest Planet to Sun : Mercury

• Farthest Planet from Sun : Neptune

Sunday 17 September 2017

CBSE Class 8 - Science - Half Yearly Sample Question Paper (2017-18) (#cbsePapers)

SCIENCE SAMPLE PAPERHALF YEARLY ASSESSMENT (2017-18)CLASS - VIII



CBSE Class 8 - Science - Half Yearly Sample Question Paper (2017-18) (#cbsePapers)


TIME-3 hrs                                                                                                    MM-80 Marks

GENERAL INSTRUCTIONS:-
1. All questions are compulsory.
2. This paper contains 4 sections: namely SECTION A- Physics, SECTION B-Chemistry,
SECTION C- Biology and SECTION D- MCQ
3. Please attempt the questions in serial order.

SECTION A (PHYSICS)

Q1. Fill in the blanks                                        (1x7= 7)
a) If light bends towards the normal as it goes from media A to medium B, then medium A is optically ______ than medium B.

b) For a normal eye, the ________ point is infinity.

c) A ______ is an instrument used in submarines to view objects on the surface of the sea.

d) The ______ constellation forms the shape of a hunter.

e) ______ was the first satellite sent up from the earth.

f) The galaxy we live in is called the __________.

g) ______ is the distance between the optical centre and the focus of a lens.


Friday 8 September 2017

CBSE Class 10 - Light - Reflection From Mirrors (Worksheet) (#cbseNotes)

Light - Reflection From Mirrors (Worksheet)

CBSE Class 10 - Light - Reflection From Mirrors (Worksheet) (#cbseNotes)



1. We get a diminished image with a concave mirror when the object is placed ____.


2. The drivers mirror used in automobiles is ____.


3. The distance of focus F from the pole P is termed as the ..................... of the mirror.


4. Mirror formula is ____.


Sunday 3 September 2017

CBSE Class 8 - Physics - Force and Pressure, Friction and Universe (Revision Sheet) (#cbseNotes)

Physics - Force and Pressure, Friction and Universe (Revision Sheet)

CBSE Class 8 - Physics - Force and Pressure, Friction and Universe (Revision Sheet) (#cbseNotes)

1. What is the necessity of pressurized cabins and airplanes?

2. You are provided with two surfaces, one smooth and one rough or uneven. Try to stick a rubber sucker on both the surfaces. Will you succeed in doing so? Give reasons for your answer.

3. Can a scuba diver dive into the ocean wearing ordinary clothes? Why or why not?

4. Why do some people experience nasal bleeding at high altitudes?

5. Explain Why, it is easier to drag a mat on floor when nobody is sitting on it but much more difficult to drag the same mat when a person is sitting on it.

6. Name the type of force in the following cases.

(a) Force exerted between heavenly bodies.
(b) Force to pull a heavy object.
(c) Force that slows down moving objects.
(d) Force due to charged particles.

Wednesday 30 August 2017

CBSE Class 10 - Chemistry - Metals and Non-Metals - Alloys Their Compositions and Uses (#cbseNotes)

Alloys - Compositions, Properties and Uses

CBSE Class 10 - Chemistry - Metals and Non-Metals - Alloys Their Compositions and Uses (#cbseNotes)


Steel
Components: Iron, Carbon

Properties: Hard and Strong

Uses:
- Construction of buildings and bridges,
- manufacture of ships
- manufacture of spare parts for automobiles






Tuesday 29 August 2017

CBSE - Class 8 - Science - Friction (Assignment Sheet) (#cbseNotes)

FRICTION - WORKSHEET


Class 8 - Physics


Multiple Choice Questions (1-10)


1. 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


2. Spring balance is a device used for measuring the _____________ acting on an object.
a) mass
b) pressure
c) force
d) None of the above

3. A matchstick struck on a matchbox catches fire easily because
a) Friction may cause fire
b) Of chemical reaction
c) Force heated the match stick
d) None of the above

Monday 28 August 2017

CBSE Class 10 / class 8 - Science - About Human Eye (#cbseNotes)

About Human Eye - Questions and Answers

CBSE Class 10 / class 8 -  Science - About Human Eye (#cbseNotes)


Human eye can be considered as an optical instrument. Light rays coming from the object to be seen enter the eye through Cornea and fall on the eye lens through the pupil of the eye.



Parts of the human eye are:


Cornea:
The transparent spherical membrane covering the front of the eye.