National Science Olympiad Forum By SOF Olympiad Trainer - Page 639

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Subject :NSO    Class : Class 8

Ans 1:

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

Ans 2:

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 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 8
positive charge is acqired

Ans 5:

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

Ans 6:

Class : Class 4

Ans 7:

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 8:

Class : Class 6

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:

Class : Class 10

Ans 2:

Class : Class 10
Protons don't move.

Ans 3:

Class : Class 5
Why

Ans 4: (Master Answer)

Class : Class 1
The correct answer is C.

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: (Master Answer)

Class : Class 1

Ans 2:

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 3:

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 4:

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

Ans 5:

Class : Class 5
cONFUSED IN d AND B

Ans 6:

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 7:

Class : Class 3
b

Ans 8:

Class : Class 3

Ans 9:

Class : Class 5
C is the correct answer

Ans 10:

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 11:

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

Ans 12:

Class : Class 5
D or B? please vote

Ans 13:

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 14:

Class : Class 5
B is the correct answer

Ans 15:

Class : Class 9
d

Ans 16:

Class : Class 7
B is the answer to this question

Ans 17:

Class : Class 5
b as Y expands more

Ans 18:

Class : Class 8
D or B not sure.

Ans 19:

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 20:

Class : Class 10
B

Ans 21:

Class : Class 9
B is the answer

Ans 22:

Class : Class 6
b

Ans 23:

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

Ans 24:

Class : Class 8
The answer should be opt.B

Ans 25:

Class : Class 5
B is the right answer

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 8
Answer is a

Ans 2:

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 3:

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

Ans 4:

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 5:

Class : Class 5
And for this question must be A

Ans 6:

Class : Class 8
WWWWRRRROOOONNNNNNNNNNGGGGGGGGGGGGGGGGG

Ans 7:

Class : Class 9

Ans 8:

Class : Class 9
The correct answer is AAAAAAA

Ans 9:

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 10:

Class : Class 10

Ans 11:

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

Ans 12:

Class : Class 8
it should be a

Ans 13:

Class : Class 8
the answer will be 'A'

Ans 14:

Class : Class 8
Yes it is A

Ans 15:

Class : Class 9
answer A

Ans 16:

Class : Class 10
thus answer is a

Ans 17:

Class : Class 9
It has to be A.

Ans 18:

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

Ans 19:

Class : Class 8
A

Ans 20:

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

Ans 21:

Class : Class 8
answer is a

Ans 22:

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 23:

Class : Class 8
Yes it should be A .

Ans 24:

Class : Class 9
Yes the 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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