National Science Olympiad Forum By SOF Olympiad Trainer - Page 639

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 4

Ans 2:

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

Ans 3:

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

Ans 4:

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 5:

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 6:

Class : Class 6

Ans 7:

Class : Class 8
positive charge is acqired

Ans 8:

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 9:

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

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Subject :NSO    Class : Class 8

Ans 1: (Master Answer)

Class : Class 1
The correct answer is C.

Ans 2:

Class : Class 10
Protons don't move.

Ans 3:

Class : Class 5
Why

Ans 4:

Class : Class 10

Ans 5:

Class : Class 10

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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 5
C is the correct answer

Ans 2:

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 3:

Class : Class 10
B

Ans 4:

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 5:

Class : Class 8
The answer should be opt.B

Ans 6:

Class : Class 5
cONFUSED IN d AND B

Ans 7:

Class : Class 9
B is the answer

Ans 8:

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

Ans 9:

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

Ans 10:

Class : Class 9
d

Ans 11:

Class : Class 3

Ans 12:

Class : Class 5
b as Y expands more

Ans 13:

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 14:

Class : Class 5
D or B? please vote

Ans 15:

Class : Class 3
b

Ans 16:

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 17:

Class : Class 6
b

Ans 18:

Class : Class 5
B is the correct answer

Ans 19:

Class : Class 8
D or B not sure.

Ans 20:

Class : Class 7
B is the answer to this question

Ans 21:

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 22:

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

Ans 23: (Master Answer)

Class : Class 1

Ans 24:

Class : Class 5
B is the right answer

Ans 25:

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

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Subject :NSO    Class : Class 8

Ans 1:

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

Ans 2:

Class : Class 9
The correct answer is AAAAAAA

Ans 3:

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

Ans 4:

Class : Class 10
thus answer is a

Ans 5:

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 6:

Class : Class 5
And for this question must be A

Ans 7:

Class : Class 9

Ans 8:

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 9:

Class : Class 10

Ans 10:

Class : Class 8
WWWWRRRROOOONNNNNNNNNNGGGGGGGGGGGGGGGGG

Ans 11:

Class : Class 8
the answer will be 'A'

Ans 12:

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 13:

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 14:

Class : Class 9
Yes the answer is A

Ans 15:

Class : Class 8
Yes it should be A .

Ans 16:

Class : Class 9
It has to be A.

Ans 17:

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

Ans 18:

Class : Class 8
A

Ans 19:

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

Ans 20:

Class : Class 8
it should be a

Ans 21:

Class : Class 8
answer is a

Ans 22:

Class : Class 9
answer A

Ans 23:

Class : Class 8
Yes it is A

Ans 24:

Class : Class 8
Answer is a

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Subject :NSO    Class : Class 3

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Subject :NSO    Class : Class 7

Ans 1:

Class : Class 9
ans is c

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Subject :NSO    Class : Class 7

Ans 1:

Class : Class 9
Plug key is also a type of switch.

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