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? The trees lose their leaves in the dry season. 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:
		Both A and R are true, and R is correct explanation of the assertion. Both A and R are true, but R is not the correct explanation of the assertion. A is true, but R is false. 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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