National Science Olympiad Forum By SOF Olympiad Trainer - Page 639

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Subject :NSO    Class : Class 9

Ans 1: (Master Answer)

Class : Class 1
The correct answer is B.

Ans 2:

Class : Class 9
pay attention to sum of their digits

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Subject :NSO    Class : Class 9

Ans 1:

Class : Class 10

Ans 2:

Class : Class 9
9.6

Ans 3:

Class : Class 9
Can u pls send the method

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Subject :NSO    Class : Class 9

Ans 1:

Class : Class 9
The answer is 12cm

Ans 2:

Class : Class 10
the answer is 12 cm

Ans 3:

Class : Class 9
The answer is 12cm

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 4

Ans 2:

Class : Class 8
positive charge is acqired

Ans 3:

Class : Class 8
The options given here are a plastic scale,a woollen cloth, an inflated balloon and a COPPER rod, not a GLASS rod. How can the options appear differently for others, since many people here are saying that there is glass rod involved? Also, plastic is an insulator of electricity, so ideally it wouldn't acquire any charge, right? SOF should give a solution to this problem.

Ans 4:

Class : Class 9
When rubbed with fur, glass will become negatively charged. However if silk is used instead of fur, glass will acquire a positive charge.

Ans 5:

Class : Class 9
glass rod when rubbed with fur, it gives electrons to fur and becomes positively charged

Ans 6:

Class : Class 8
This is wrong, yet nothing has been done to fix it. It has been discovered to be wrong FOUR YEARS ago!

Ans 7:

Class : Class 8
Plastic is unable to be charged.. Wrong answer!

Ans 8:

Class : Class 8
Answer is A... positive charge is acquire by the glass rod

Ans 9:

Class : Class 6

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 10
Protons don't move.

Ans 2:

Class : Class 10

Ans 3:

Class : Class 10

Ans 4:

Class : Class 5
Why

Ans 5: (Master Answer)

Class : Class 1
The correct answer is C.

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Subject :NSO    Class : Class 5

Ans 1:

Class : Class 5
D

Ans 2:

Class : Class 8
It should be option C. It should be discouraged.

Ans 3:

Class : Class 5
D

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Subject :NSO    Class : Class 4

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Subject :NSO    Class : Class 10

Ans 1: (Master Answer)

Class : Class 1
The correct answer is D.

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Subject :NSO    Class : Class 5

Ans 1:

Class : Class 7
Sumit Singhal , this is a bimetallic metal . Here , the two metals cannot go away from each other . So here , if y expands than x will also expand , and if x expands than y will also expand . I am getting confusion between A and B .

Ans 2:

Class : Class 5
D or B? please vote

Ans 3:

Class : Class 4
sof does not reply that is why we are confused

Ans 4:

Class : Class 3
b

Ans 5:

Class : Class 5
B is the correct answer

Ans 6:

Class : Class 5
C is the correct answer

Ans 7:

Class : Class 5
b as Y expands more

Ans 8:

Class : Class 1
The answer is B because the question says that he HEATED both the metals (most metals expand on heating) and Y has expanded more than X

Ans 9:

Class : Class 5
B is the right answer

Ans 10:

Class : Class 8
D or B not sure.

Ans 11:

Class : Class 10
B

Ans 12:

Class : Class 4
ans should be D as if metal x contracts and metal y expands then the 2 metals will bend inward an as an ellusion we see that y is longer than x

Ans 13:

Class : Class 8
The answer should be opt.B

Ans 14:

Class : Class 9
d

Ans 15:

Class : Class 7
B is the answer to this question

Ans 16:

Class : Class 9
B m kids because Y is only curled much . dont get angry

Ans 17:

Class : Class 4
iron-nickel alloy notable for its lack of expansion or contraction with temperature changes. hence all metals do NOT expand

Ans 18: (Master Answer)

Class : Class 1

Ans 19:

Class : Class 3
as if we will contract metal x so it is not neccessery that y will contract if we contract metal y x has to be conyracted with it ans should be a

Ans 20:

Class : Class 3

Ans 21:

Class : Class 5
cONFUSED IN d AND B

Ans 22:

Class : Class 3
All metal expands on heating. Here metal Y expands more which leads to curling of both X and Y. B is the correct option.

Ans 23:

Class : Class 9
B because if Y expands and X contracts, X will be a lot smaller than Y. Here, both are almost the same size.

Ans 24:

Class : Class 9
B is the answer

Ans 25:

Class : Class 6
b

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 8
A

Ans 2:

Class : Class 8
Yes it should be A .

Ans 3:

Class : Class 5
And for this question must be A

Ans 4:

Class : Class 9
answer A

Ans 5:

Class : Class 9
Yes the answer is A

Ans 6:

Class : Class 10
my apologies for the previous explanation answer is : C

Ans 7:

Class : Class 8
the answer will be 'A'

Ans 8:

Class : Class 10
the answer is wrong.....it should be a

Ans 9:

Class : Class 9
The correct answer is AAAAAAA

Ans 10:

Class : Class 8
WWWWRRRROOOONNNNNNNNNNGGGGGGGGGGGGGGGGG

Ans 11:

Class : Class 7
i do feel that correct answer is A.as P has to be electroplated ,it must be on cathode(-ve).so,correct is =A

Ans 12:

Class : Class 8
it should be a

Ans 13:

Class : Class 8
answer is a

Ans 14:

Class : Class 9
It has to be A.

Ans 15:

Class : Class 8
Yes it is A

Ans 16:

Class : Class 10

Ans 17:

Class : Class 10
In reactivity series hydrogen is below zinc and is less reactive than zinc. As hydrogen below zinc therefore will reduce more and earlier than zinc , hence will go to cathode and zinc will reduced or deposit at anode. therefore P will be connected to R and Q to S.hence ans is :C

Ans 18:

Class : Class 8
cation(Zn2 ) must be deposited to the cathode.

Ans 19:

Class : Class 8
Answer is a

Ans 20:

Class : Class 9
I will go mad with the number of wrong answers in this website.. answer should be a. For example when a spoon has to be electroplated with copper, copper is ALWAYS ON ANODE and the spoon is ALWAYS ON CATHODE. Why different logic is used here?

Ans 21:

Class : Class 6
answer should be A, as hydrogen is not released at cathode if the other cation is Zinc or below in the electrochemical series

Ans 22:

Class : Class 10
What is the correct answer A or C ???????

Ans 23:

Class : Class 9

Ans 24:

Class : Class 10
thus answer is a

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