National Science Olympiad Forum By SOF Olympiad Trainer - Page 640

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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
B is the answer to this question

Ans 2:

Class : Class 6
b

Ans 3:

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 4:

Class : Class 10
B

Ans 5:

Class : Class 5
C is the correct answer

Ans 6:

Class : Class 3
b

Ans 7:

Class : Class 5
D or B? please vote

Ans 8:

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 9:

Class : Class 3

Ans 10:

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 11:

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 12:

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

Ans 13:

Class : Class 5
B is the right answer

Ans 14:

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

Ans 15: (Master Answer)

Class : Class 1

Ans 16:

Class : Class 8
The answer should be opt.B

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:

Class : Class 8
D or B not sure.

Ans 19:

Class : Class 5
b as Y expands more

Ans 20:

Class : Class 5
B is the correct answer

Ans 21:

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 22:

Class : Class 9
B is the answer

Ans 23:

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 24:

Class : Class 5
cONFUSED IN d AND B

Ans 25:

Class : Class 9
d

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 5
And for this question must be A

Ans 2:

Class : Class 8
it should be a

Ans 3:

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

Ans 4:

Class : Class 8
Yes it is A

Ans 5:

Class : Class 8
WWWWRRRROOOONNNNNNNNNNGGGGGGGGGGGGGGGGG

Ans 6:

Class : Class 9
Yes the answer is A

Ans 7:

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 8:

Class : Class 8
the answer will be 'A'

Ans 9:

Class : Class 8
answer is a

Ans 10:

Class : Class 9
It has to be A.

Ans 11:

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

Ans 12:

Class : Class 8
Answer is a

Ans 13:

Class : Class 9
answer A

Ans 14:

Class : Class 8
Yes it should be A .

Ans 15:

Class : Class 9
The correct answer is AAAAAAA

Ans 16:

Class : Class 9

Ans 17:

Class : Class 10

Ans 18:

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

Ans 19:

Class : Class 8
A

Ans 20:

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

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 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 23:

Class : Class 10
thus answer is a

Ans 24:

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

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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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Subject :NSO    Class : Class 5

Ans 1:

Class : Class 5
sedimentation and decantation is the answer . but filtration can not come because we can see in the picture itself that the particles are big ,that's why sedimentation and decantation . if the particles are small but yet insoluble , then only it is filtration . I hope that you understood.

Ans 2:

Class : Class 10
Yes, but in the given figure it is sedimentation

Ans 3:

Class : Class 10
c

Ans 4:

Class : Class 9
it needs to be sedimentation and decantation because the insoluble material present in the liquid is quite heavy you only perform filtration when the particles float over the surface of the water

Ans 5:

Class : Class 5
Ya, filtration can also remove insoluble impurities but in this case sedimentation and decanation is more appropriate answer.

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Subject :NSO    Class : Class 7

Ans 1:

Class : Class 9
every single sound has its own secondary waves, so the correct option must be option C.

Ans 2:

Class : Class 7
correct option is c

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 9

Ans 2:

Class : Class 8
Hi, the statement 2 is true but just tells about the type type combustion to which the reaction given in statement belong. it does not tell about actual cause of burning of phosphorus in air at room temperature. the reason for statement 1 is that phosphorus is a highly reactive element that's why burns in air at room temperature.

Ans 3:

Class : Class 5

Ans 4:

Class : Class 8

Ans 5:

Class : Class 9

Ans 6:

Class : Class 8

Ans 7:

Class : Class 8
Actually, the solution is opposite to the correct answer

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