SCIENCE / CLASS – VIII/ CHAPTER - LIGHT

  SCIENCE /   CHAPTER - LIGHT

Q1. Fill ups:

1) The image formed by a plane mirror shows the phenomenon of -------  inversion.

2) Perpendicular at the point of incidence is -------- 

3) Splitting up of light into its color is known as  ----------- of light.

4) Part of retina which is devoid of light sensitive cells  ----------.

5) During near vision, ciliary muscles -------- , while during distant vision, they expand.

6)  --------- lens is present in the eyes.

7)  ------------ protect the inner structure of the eyes.

8) The day birds like Kite, Eagle have more ---------- & fewer -----------  .

9) Reflection of light by a smooth polished surface is  ------- reflection.

10) The ---------- nerves connects the eyes to brain.

Q2. Choose the correct answer:

1. Braille System was developed in

a) 1891 c) 1791

b) 1888 d) 1821

2. The image formed by a plane mirror is 

a) Always real

b) Always virtual

c) Sometimes real & sometimes Virtual depending upon the distance of object from the mirror. 

d) Real but diminished

3. The no. of multiple images formed by two plane mirrors, if the angle between them is 72˚

a) 4        c) 5

b) 6           d) 7

4. A person is standing 5m away from a plane mirror. What will be the distance between him & the image?

a) 5m               c) 0m

b) 10m         d) 15m

Q3. Name the following:

a) The most popular resource for visually challenged person to read & write.

b) The ray which strikes any surface.

c) Light sensitive cells in the eye.

d) A smooth, shining surface, which rebounds the light back in the same or different direction.

Q3. Why do night birds have extraordinary night vision?

Q4. How the persistence of vision is helpful in making still pictures moving?

 Q5. Describe the functions of (a) cornea (b) pupil (c) ciliary muscles (d) iris

Q6. Why are the multiple images seen when two plane mirrors are placed at an angle between them?

Q7. Why is Vitamin A essential for us?

Q8. What are the common eye defects? Give their causes and corrective measures.

Air and water pollution /CLASS 8 , SCIENCE WORKSHEET

Air and water pollution

1. Write full form for the following.

a) CNG ..........................

b) CFC ..........................

c) LPG ..........................

d) RRR ..........................

2. Choose the correct option -

i) Which gas is not air-pollutant.

a) Nitrogen dioxide b) Oxygen

c) Carbon monoxide d) Sulphur dioxide

ii) Which of the following is the natural source of air pollution.

a) Smoke from factories b) Pollution from automobiles

c) Wood for fuel d) Volcanic eruptions

iii) Drinking water

a) Should be clean

b) Should be odourless

c) clean, odourless and pure

d) None of the above

iv) We can reduce air pollution by

1) Plantation

2) By walking

3) By cycling

4) All of the above

3. Write names of two green - house gases

1 .....................................  2 ......................................

 . Name two gases responsible for acid rain.

1 .............................  2 ..................................

5. Mention any two causes of Air - Pollution

1) ...................................... 2)................................ 

6. Name any two causes of water - Pollution

1).................................... 2)..................................  

SCIENCE / CLASS – VIII

  SCIENCE / CLASS – VIII  

CHAPTER – CROP PRODUCTION

Q1. Fill ups:

1. ------------ compete with main crops for nutrients.

2. Grains are separated from harvested crops by using ----------- &  ---------

3. Excess water in the fields may cause a condition called ---------- .

4. ---------- bacteria lies in the root nodules of leguminous plants helps in fixing of atmospheric nitrogen.

5. Bulk storage of grains is done in ----------- & ------------- .

6. The produced crop is stored in different containers, after being sundried, to prevent the attack of  ----------- .

Q2. Name the following:

1. Equipment used to level the tilled land. ----------------------

2. Process of leaving the land uncultivated for one or more seasons. ---------------------

3. Management & care of domestic animals.---------------------

4. Man made chemical substance rich in inorganic nutrients.---------------------

5. Separation of grain from its chaff or husk after threshing with the help of wind. --------------------

6. An agricultural implement used to sow seeds. ---------------------

7. The process of removing weeds from the field. ---------------------

8. Organisms which cause damage to the crops & make them unfit for human consumption.---------------------  

Q3. Match the following:

1. Harvesting         (a) Rabi

2. Wheat              (b) Fertilizer

3. Grass            © Agricultural implement

4. Irrigation          (d) Sickle

5. Urea                 (e) Weed

6. Plough                      (f) Drip system

Q4. Choose the correct option:

1. Which of the following is/are post harvesting technique(s)?

(a) Winnowing (c) Storage of food grains

(b) Threshing (d) All of these

2. NPK fertilizers contains

(a) Nitrogen ,Potassium & Calcium (c) Nitrogen, Phosphorus& Potassium

(b) Nitrogen, Potassium & Phosphorus (d) Nitrogen, Phosphorus &Keratin

3. Manual removal of weeds is done by:

(a) Trowel (c) Insects

(b) Weedicides (d) Tilling

4. Major source of water in fields is:

(a) River (c) Ponds

(b) Tube wells (d) Rainfall

 Q5. What is crop rotation?

Q6. Why organic manure is considered better than chemical fertilizer?

Q7. What precautions should be taken care while storing harvested grains? 

Q8. List some advantages of preparing soil.

Q9. A farmer was using lot of fertilizers for the improvement of his produce from the field.

List any two harmful effects of fertilizers on environment.

How will you convince him to restrict the use of fertilizers?

SCIENCE WORKSHEET

SCIENCE WORKSHEET

A. Multiple Choice Questions

1. Which of the following is not a fossil fuel?

a. Coal

b. Petroleum

c. Natural gas

d. Wood

2. Which of the following is not a product of coal?

a. Coke

b. Coal

c. Coal Gas

d. Natural Gas

3. Which of the following is not a petroleum product?

a. Kerosene

b. Paraffin wax

c. Lubricating Oil

d. Coke

4. Which of the following is an inexhaustible natural resource?

a. Coal

b. Natural gas

c. Air

d. Petroleum

5. Which of the following is an exhaustible natural resource?

a. Natural gas

b. Sun light

c. Air

d. None of these

6. Which of the following is used in production of electricity?

a. Coal

b. Coke

c. Coal gas

d. None of above

7. In these days for metalling of roads which of the following is used in place of coal-tar?

a. Petroleum product

b. Bitumen

c. Paraffin wax

d. None of above

8. The advantages of CNG is that it is a

a. Compressed gas

b. Natural gas

c. Supplied through pipes

d. All the above

B. One word substitution :

1. The superior quality of coal having 95% carbon is called as ------------------.

2. A mixture of hydrogen, methane and carbon monoxide is called as ----------------- .

3. A substance which produces sufficient energy on burning is called as  --------------------- .

4. A liquid called black gold in known as  ----------------- .

5. A kind of fuel used to cook food is called ------------------- .

  .

WORKSHEET SCIENCE (Class 8 )

WORKSHEET SCIENCE (Class 8 )

MULTIPLE CHOICE QUESTIONS :

1. The variety of coal which has highest content of carbon :

a) Peat     b) Bituminous c) Anthracite d) Liquate

2. The microbe that reproduce only inside the body of the host organism :

a) Bacteria    b) Virus c) Protozoa d) Fungi

3. Deforestation means :

a) Cleaning of forests   b) To grow plants c) To look after plants d) None of these

4. Project - Tiger means :

a) Hunting of tigers b) Rearing of tigers c) Survival & maintanance of tigers d) All of these.

5. Bats can hear the sound of frequency :

a) Less than 20 hz b) More than 20 khz c) Between 20 hz and 20 khz d) All of these.

FILL IN THE BLANKS :

1. The image of our face in a plane mirror is an example of  ----- image.

2. The process of depositing a layer of any desired metal on another material by means of electricity is called -------- .

3. Large amplitude of sound vibrations will produce  ------- .

4. Animals whose numbers are diminishing to a level and they might face extinction are

called --------- . .

5. Distilled water is ---------  of electricity.

SHORT ANSWER TYPE QUESTIONS :

1. Give three examples of electroplating.

i) .................................... ii) ................................... iii) ....................................

2. What do you mean by music sound ?

3. What is fractional distillation ?

4. Name the carrier of Dengue fever.

5. Why should we save our fossil fuels ?

SCIENCE REVISION WORKSHEET / CLASS -VIII

SCIENCE REVISION WORKSHEET 

1. What is spring balance?

2. Name two objects having streamlined body to reduce friction.

3. Differentiate between :

a. Sliding Friction and Static Friction.

b. Rapid Combustion and Spontaneous Combustion.

4. Give reasons.

a. The tyres of vehicles are made with grooves.

b. All machines in industries and factories need to be lubricated regularly.

c. Bodies of aeroplanes are streamlined.

5. What are the necessary conditions for the combustion to take place.

  _

6. Kapil burnt a piece of coal and paper separately. He observed that the paper burnt with a flame while the piece of coal burnt without a flame. Why is it so?

7. Why should fossil fuels be used judiciously?