National Science Olympiad Forum By SOF Olympiad Trainer

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Subject :NSO    Class : Class 5

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Subject :NSO    Class : Class 10

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Subject :NSO    Class : Class 9

Ans 1:

Class : Class 9
ans c

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Subject :NSO    Class : Class 7

Fill in the blanks by choosing the correct option.Turmeric is one of the most commonly used spices in our kitchen. It leaves a yellow stain on white clothes. On rubbing with soap which is p in nature, the yellow stain changes to q colour. Now, if we pour some r containing s over this stain, it again becomes yellow in colour due to t .

P Q R S T
A Alkaline Red Lemon juice Acetic acid Formation of water
B Acidic Green Lime Lime Sodium hydroxide Neutralisawatertion reaction
C Neutral Dark pink Lime water Potassium hydroxide Formation of water
D Alkaline Red Lemon juice Citric acid Neutralisation reaction


Ans 1:

Class : Class 7
answer is D ) this is because soap is alkaline in nature so p is alkaline then we can cancel out b or c then basic or alkaline substances turn red when rubbed on turmeric paper. hen they have mentioned in the answer that it has to be lemon juice and it contains citric acid or vitamin c the reaction turns it back to yellow that reaction is known as neutralization reaction

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Subject :NSO    Class : Class 8

Study the given dichotomous key and select the correct option.
I. a. It is a unicellular organism - go to II
b. It is multicellular organism - go to III
II. a. It contains chlorophyll - P
b. It does not contain chlorophyll - Q
III. a. It is used in production of antibiotics - R
b. It decomposes the organic waste and dead plants and animals - S

AP could be Spirogyra whereas Q could be Rhizopus.
BR could be Penicillium whereas S could be diatoms.
CP could be Chlamydomonas whereas R could be Streptomyces.
DNone of these


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Subject :NSO    Class : Class 8

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Subject :NSO    Class : Class 7

Refer to the given diagram and identify the correct statements.
(i) J produces saliva which contains enzyme amylase that breaks down cellulose and starch into simple sugars.
(ii) Digestive juices secreted by N contain enzyme which breakdown the proteins into simple substances. N also secretes HCl, which kills harmful microorganisms present in food.
(iii) K is the largest gland in the body and its secretion helps in digestion of fats.
(iv) M bears finger like projections called villi and it stores digestive juice secreted by liver.
(v) P helps in absorption of food and transports digested food to different organs through blood capillaries.
(vi) Q is small structure at junction of small and large intestine which stores faecal matter until egestion.
(vii) Digestive juices of L help in digestion of proteins, carbohydrates and fats.
(viii) O absorbs water and minerals from the chyme.


A(ii), (iii), (v), (vii) and (viii) only
B(i), (iii), (iv), (vi) and (viii) only
C(ii), (iv), (v) and (vi) only
D(i), (ii), (v), (vi) and (viii) only


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Subject :NSO    Class : Class 7

Read the given statements and state (T) for true and (F) for false ones.
I. A compound can be broken down into its constituent elements by chemical methods.
II. A compound always contains the same elements combined together chemically in a fixed ratio.
III. A compound retains the properties of its constituent elements.
IV. When two or more elements or compounds are brought together, they always react chemically.
V. Tap water is a compound.

  I II III IV V
A (F) (T) (T) (F) (F)
B (T) (T) (F) (F) (F)
C (F) (F) (F) (T) (T)
D (T) (F) (T) (F) (T)


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Subject :NSO    Class : Class 7

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Subject :NSO    Class : Class 5

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