SCIENCE ANSWER TO REVISION BANK QUESTION TERM 1

 

Section A
1.	X is a separation technique used only when the components of a solid-solid mixture have different sizes. Identify X.				1
	(a)		Winnowing
	(b)		Sieving
	(c)		Threshing
	(d)		Magnetic separation
	ans:		(b) Sieving		An
			Ch 5: Separating Mixtures, Pg- 48
2.	Identify X in the given Venn diagram.				1
	Natural fibre Animal source X It has lustre
	(a)		Cotton
	(b)		Wool
	(c)		Silk
	(d)		Nylon
	ans:	(c) Silk			Ap
		Ch 3: Fibre to Fabric, Pg-26
3.	In ancient times, the length of a foot, the width of a finger, and the distance of a step were commonly used as different units of measurements. However, everyone's body parts could be of slightly different sizes. This must have caused confusion in measurement. In 1790, the French created a standard unit of measurement called the metric system. For the sake of uniformity, scientists all over the world have accepted a set of standard units of measurement. The system of units now used is known as the International System of Units (SI units).
	Which of the following is NOT a non-standard unit of measurement?				1
	(a)		Metre
	(b)		Foot span
	(c)		Hand span
	(d)		Cubit
	ans:		(a) Metre		R
4.	In ancient times, the length of a foot, the width of a finger, and the distance of a step were commonly used as different units of measurements. However, everyone's body parts could be of slightly different sizes. This must have caused confusion in measurement. In 1790, the French created a standard unit of measurement called the metric system. For the sake of uniformity, scientists all over the world have accepted a set of standard units of measurement. The system of units now used is known as the International System of Units (SI units).
	One gram has been divided into 1000 equal parts; each part is equal to:				1
	(a)		One ton
	(b)		One kilogram
	(c)		One milligram
	(d)		One quintal
	ans:	(b) One milligram			U
5.	In ancient times, the length of a foot, the width of a finger, and the distance of a step were commonly used as different units of measurements. However, everyone's body parts could be of slightly different sizes. This must have caused confusion in measurement. In 1790, the French created a standard unit of measurement called the metric system. For the sake of uniformity, scientists all over the world have accepted a set of standard units of measurement. The system of units now used is known as the International System of Units (SI units).
	An ant moves as shown in the diagram. Which of the following can be used to determine the distance covered by this ant?				1
	(a)		A 15 cm scale and a metre scale
	(b)		Only a metre scale
	(c)		Hand span and a metre scale
	(d)		Thread and a metre scale
	ans:	(d) Thread and a metre scale			Ap
		Ch 10: Motion and Measurement, Pg-136, 138 and 139
Section B
6.	(a)	For the given questions two statements are given – one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:			1
		(I)          Both A and R are true and R is correct explanation of the assertion A       (II)          Both A and R are true, but R is not the correct explanation of the assertion A.      (III)          A is true but R is false.     (IV)          A is false but R is true.
		(i)		Assertion:  A gold coin floats on water. Reason: A substance will only float on a liquid if its density is less than that of the surrounding liquid.
		ans:		(IV). A is false but R is true.
				Ch 3: Grouping Materials, Pg-38	An
		(ii)		Assertion: Smoke is an example of a mixture. Reason:  A mixture is a combination of two or more pure substances.
		ans:		(I). Both A and R are true and R is correct explanation of the assertion A.
				Ch 5: Separating Mixtures, Pg- 43	An
	(b)	(i)		Name the process of conversion of water vapour into its liquid form.	1
		ans:		Condensation	R
				Ch 5: Separating Mixtures, Pg- 51
		(ii)		Name the type of motion that repeats itself at regular intervals of time.	1
		ans:		Periodic motion	U
				Ch 10: Motion and Measurement, Pg-144
		(iii)		Fill in the blank:
				The substances which disappear or dissolve completely in water are called soluble substances.	1
				Ch 4: Grouping Materials, Pg-35	R
7.	The distance between Amay’s house and his school is 5750 m. Express this distance in km.				2
	ans:	1 km = 1000 m                                                   1 mark So, 5750 m =  km = 5.75 km Thus, the distance between Amay’s house and his school is 5.75 km.    1 mark			Ap
		Ch 10: Motion and Measurement, Pg-138
8.	Tulsi wants to separate a mixture of oil and water. Name the method she can use to separate oil and water. Give reasons for your answer.				3
	ans:	·          Oil and water can be separated by sedimentation and decantation.                                                                        2 marks  ·          Water is heavier than oil. Thus, it settles to the bottom if left undisturbed for some time. The oil can then be decanted or poured out.                                                                           1 mark			An
		Ch 4: Separating Mixtures, Pg-55
9.	Answer the following questions:				5 R
	(a)	State the climatic condition favourable for the growth of the jute plant.
	ans:	Jute plant grows well in the regions with high temperature and heavy rainfall.
	(b)	In which states of India is jute mainly grown?
	ans:	Jute is mainly grown in the states of West Bengal, Bihar and Assam.
	(c)	What is retting?
	ans:	The process of separating the fibres from the rotten stem by hand is known as retting.
	(d)	What is spinning? Name two devices that can be used for spinning.
	ans:	·       The process of creating yarn from fibres is known as spinning. 1 mark ·       Takli and Charkha are two devices that can be used for spinning.                                                          1 mark
		Ch 3: Fibre to Fabric, Pg-25, 27 and 28

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