Friday, March 4, 2022

SCIENCE Revision Question Bank QUESTION & ANS

 

PODAR INTERNATIONAL SCHOOL 

Revision Question Bank (2021-22)

Std: VII

Answer Scheme

Subject: Science


Portion:  

  • Ch 4: Heat and its transfer

  • Ch 11: Reproduction in Plants

  • Ch 15: Electricity and its effects

  • Ch 16: Water - A precious Treasure

  • Ch 17: Forests - Our Lifeline



Section A 



The full form of MCB is:

1



Mini Circuit Breaker




Mini Connection Breaker




Miniature Connection Breaker




Miniature Circuit Breaker



ans:

(d)   Miniature Circuit Breaker 




Ch 15: Electricity and its effects, Pg-254







Read the statements given below and identify X and Y. 

X is a tiny pore in the seed coat through which water and oxygen enter during germination.

Y is a part on the embryo beneath the cotyledons directly above the root.

1



X-Micropyle, Y- Hypocotyl




X-Epicotyl , Y- Hypocotyl




X-Micropyle, Y- Epicotyl




X- Hypocotyl, Y- Micropyle



ans:

(a) X-Micropyle, Y- Hypocotyl




Ch 11: Reproduction in plants, Pg-183 











Identify the part labelled as X in the given figure.

1





Gong




Electromagnet




Soft iron strip




Spring



ans:

(b)   Electromagnet




Ch 15: Electricity and its effects, Pg-257







Study the given passage and answer the following question.

1


Tropical rainforests are characterised by heavy rainfall. The most abundant rainforests are situated on the south-western coast of Kerala. Some other parts in India where rainforests can be found are in the states of Assam, West Bengal, Meghalaya, Arunachal Pradesh, Nagaland, Tripura, Western Ghats and the Andaman and Nicobar Islands. Deciduous forests are so called because the trees of these forests seasonally shed all their leaves for about six to eight weeks. Trees in tropical deciduous forests lose their leaves in the dry season and regrow them in the rainy season. The deciduous forests are most commonly found on the eastern slopes of the Western Ghats, Kerala, Chotta Nagpur plateau, East Madhya Pradesh, South Bihar and West Odisha.



In which of the following place will you find deciduous forests?




Meghalaya 




South Bihar




Arunachal Pradesh




Nagaland



ans:

(b)    South Bihar




Ch 17: Forests - Our Lifeline -285  







Study the given passage and answer the following question.

1


Tropical rainforests are characterised by heavy rainfall. The most abundant rain forests are situated on the south-western coast of Kerala. Some other parts in India where rain forests can be found are in the states of Assam, West Bengal, Meghalaya, Arunachal Pradesh, Nagaland, Tripura, Western Ghats and the Andaman and Nicobar Islands. Deciduous forests are so called because the trees of these forests seasonally shed all their leaves for about six to eight weeks. Trees in tropical deciduous forests lose their leaves in the dry season and regrow them in the rainy season. The deciduous forests are most commonly found on the eastern slopes of the Western Ghats, Kerala, Chotta Nagpur plateau, East Madhya Pradesh, South Bihar and West Odisha. 



Which of the given statement/s best describes tropical rainforests?

  1. The trees lose their leaves in the dry season.

  2. They are characterised by heavy rainfall.




Only I




Only II




Both I and II




Neither I and nor II



ans:

(b)   Only II




Ch 17: Forests - Our Lifeline -285  


































Section B




For question number (i) and (ii), two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (I), (II), (III) and (IV) as given below:




  1. Both A and R are true, and R is correct explanation of the assertion.

  2. Both A and R are true, but R is not the correct explanation of the assertion.

  3. A is true, but R is false.

  4. A is false, but R is true.





Assertion:  It is very important that seeds get scattered away from the parent plant.

Reason:  Seeds of a plant compete with the parent plant for essential nutrients, space, sunlight, water and air.

1



ans:

(I) Both A and R are true, and R is correct explanation of the assertion.





Ch 11: Reproduction in Plants, Pg- 183










Assertion: Air conditioners are fitted at the top in a room.

Reason: When an air conditioner fitted at the top, is switched on, the air molecules close to the floor get cooled, they rise upwards and the hot air from the top sinks towards the floor.

1



ans:

(III) A is true, but R is false.





Ch 4: Heat and its transfer, Pg-61










What is an aquifer?

1



ans:

The reservoir of water that gets collected in the empty spaces between the water table and the bedrock is called the aquifer.





Ch 16: Water - A precious Treasure, Pg-266





Name the process of conversion of vapour into a liquid.

1



ans:

Condensation





Ch 16: Water - A precious Treasure, Pg-264





What is the complex feeding system of interlocking and interdependent food chains called?

1



ans:

Food web





Ch 17: Forests - Our Lifeline -282  







Define the following terms:

2



Reproduction



ans:

The process of producing offsprings (young ones) of their own kind is known as reproduction.




1 mark




Ch 11: Reproduction in Plants, Pg- 170




Perfect flower



ans:

A flower having both male and female reproductive parts is called a perfect flower.




1 mark




Ch 11: Reproduction in Plants, Pg- 179







State any three advantages of using mercury in a thermometer.

3


ans:

  • Being a metal, mercury is a good conductor of heat and needs very little heat to expand.

  • It spreads evenly as the temperature rises.

  • Its readings are legible because of its silvery shine appearance.

  • It does not stick to the walls of the capillary of a thermometer.

  • It maintains its liquid form over a wide range of temperature. 

  • Its boiling point is at 356.73° C and freezing point is at -38.87° C.

(accept any three points)




3 marks




Ch 4: Heat and its transfer, Pg-52




















What is an electromagnet? 

5


ans:

An electromagnet is a device which behaves like a magnet until current is flowing through a solenoid.




1 mark




Ch 15: Electricity and its effects, Pg-256








Why are strong electromagnets used in heavy industrial cranes?



ans:

Strong electromagnets are used in heavy industrial cranes to lift, move and drop heavy iron and steel objects like cars.




1 mark




Ch 15: Electricity and its effects, Pg-257








State any three factors on which the amount of heat produced by the flow of current through a wire depends on.



ans:

The amount of heat produced by the flow of current through a wire depends upon the following factors.

  • Material of the wire

  • Thickness of the wire

  • Length of the wire

  • Amount of the current flowing through the wire 

(accept any three points)




3 marks




Ch 15: Electricity and its effects, Pg-253






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