National Science Olympiad Forum By SOF Olympiad Trainer - Page 586

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Subject :NSO    Class : Class 5

Ans 1:

Class : Class 9
d

Ans 2:

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 3:

Class : Class 8
The answer should be opt.B

Ans 4:

Class : Class 8
B is the answer

Ans 5:

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 6:

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 7:

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

Ans 8:

Class : Class 8
B m kids because Y is only curled much . dont get angry

Ans 9: (Master Answer)

Class : Class 1

Ans 10:

Class : Class 2
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 7
B is the answer to this question

Ans 12:

Class : Class 5
cONFUSED IN d AND B

Ans 13:

Class : Class 5
B is the correct answer

Ans 14:

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

Ans 15:

Class : Class 8
B because if Y expands and X contracts, X will be a lot smaller than Y. Here, both are almost the same size.

Ans 16:

Class : Class 3
b

Ans 17:

Class : Class 5
b as Y expands more

Ans 18:

Class : Class 5
D or B? please vote

Ans 19:

Class : Class 10
B

Ans 20:

Class : Class 3

Ans 21:

Class : Class 5
C is the correct answer

Ans 22:

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 23:

Class : Class 7
D or B not sure.

Ans 24:

Class : Class 6
b

Ans 25:

Class : Class 5
B is the right answer

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Subject :NSO    Class : Class 8

The diagram shows a beaker containing a solution of zinc sulphate and two carbon electrodes. A battery is placed next to it. In order that the electrode P be plated with zinc,


A P must be connected to S and Q to R
B P must be connected to Q and S to R
C P must be connected to R and Q to S
D P and Q must be connected to R.


The answer would be a as znso4 wold breakdown into zn 2and so42-ions .the zn 2 would be attracted towards cathode(negative terminal) so p would be attached to negative terminal and therefore the answer is a.

Ans 1:

Class : Class 8
answer is a

Ans 2:

Class : Class 9
The correct answer is AAAAAAA

Ans 3:

Class : Class 9

Ans 4:

Class : Class 8
A

Ans 5:

Class : Class 8

Ans 6:

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 7:

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

Ans 8:

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

Ans 9:

Class : Class 8
the answer will be 'A'

Ans 10:

Class : Class 8
it should be a

Ans 11:

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

Ans 12:

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 13:

Class : Class 8
Answer is a

Ans 14:

Class : Class 8
Yes it is A

Ans 15:

Class : Class 9
Yes the answer is A

Ans 16:

Class : Class 8
Yes it should be A .

Ans 17:

Class : Class 9
answer A

Ans 18:

Class : Class 8
WWWWRRRROOOONNNNNNNNNNGGGGGGGGGGGGGGGGG

Ans 19:

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 20:

Class : Class 10
thus answer is a

Ans 21:

Class : Class 9
It has to be A.

Ans 22:

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

Ans 23:

Class : Class 6
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 24:

Class : Class 5
And for this question must be A

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Subject :NSO    Class : Class 3

A note is shown here which Ravi has made about different types of house. Unfortunately when he had finished writing, some ink spilt over the page and covered some of the key words.
A wooden house made on a boat is called . It is common in Kashmir and . In areas with heavy rainfall houses are common. are built of snow and are found in very cold countries.
Select the correct sequence of hidden words to complete the note.

A Caravan, Rajasthan, Tent, Igloos
B Houseboat, Kerala, Stilt, Igloos
C Houseboat, Delhi, Kutcha, Igloos
D Tent, Karnataka, Caravan, Igloos


Ans 1:

Class : Class 3
B

Ans 2:

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 10
Yes, but in the given figure it is sedimentation

Ans 2:

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

Ans 3:

Class : Class 10
c

Ans 4:

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 5:

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

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Subject :NSO    Class : Class 7

Ans 1:

Class : Class 7
correct option is c

Ans 2:

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

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Subject :NSO    Class : Class 8

Read the given statements and select the correct option.
Statement 1 : Phosphorus burns in air at room temperature.
Statement 2 : It is an example of spontaneous combustion.

A Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.
B Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.
C Statement 1 is true and statement 2 is false.
D Both statements 1 and 2 are false.


I say it is option a but they say it is b....But isn’t this definitely due to spontaneous combustion?

Ans 1:

Class : Class 9

Ans 2:

Class : Class 5

Ans 3:

Class : Class 8

Ans 4:

Class : Class 5

Ans 5:

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.

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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 9

Ans 2:

Class : Class 9
Both Wheat and Maize require rotation of crops.

Ans 3:

Class : Class 8

Ans 4:

Class : Class 8
Why so? In both the cases soybean is present.

Ans 5:

Class : Class 8
Think in the way of leguminous crops

Ans 6:

Class : Class 6
yeah right Triguna!!! in both cases soybean is present? why so?

Ans 7:

Class : Class 9
Supposed to be only ABecause mustard is a non leguminous plantEven it can be rotated with soyabean

Ans 8:

Class : Class 8

Ans 9:

Class : Class 8
The protein requirement of mustard is fulfilled by the ribozome present in root nodules of soyabean?

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Subject :NSO    Class : Class 6

Ans 1:

Class : Class 6
The shadow will be whole black as the book is an opaque object and will not allow any light to pass through it so on the screen it will form a shadow. And the rest that is the ring, no light will reach it thus how can its shadow be formed?

Ans 2:

Class : Class 10
iT IS NOT LAPTOP'S MISTAKE IT IS THE WEBSITE'S MISTAKE ITSELF.

Ans 3:

Class : Class 10
They did not give options so that is why it went wrong. these kind of incidents happen very frequently in SOF

Ans 4:

Class : Class 10
NO OPYIONS!

Ans 5:

Class : Class 6
No options

Ans 6:

Class : Class 10
no options

Ans 7:

Class : Class 6
They did not give options on my ipad .

Ans 8:

Class : Class 6
They're not even giving me options

Ans 9:

Class : Class 9

Ans 10:

Class : Class 8
they didn't give the options to my computer

Ans 11:

Class : Class 6
They did not provide options on my laptop but option C is correct.

Ans 12:

Class : Class 6
they should be more careful

Ans 13:

Class : Class 7
my laptop din't provide the options

Ans 14:

Class : Class 9
they did not give options

Ans 15:

Class : Class 7
They didn't give options

Ans 16:

Class : Class 9

Ans 17:

Class : Class 10
They did not give the options on my iPad so I couldn't see which was the correct ans. something needs to be done about this problem.

Ans 18:

Class : Class 6
they MUST and SHOULD be more CAREFUL. No options??? Then, how should we answer their question??? they take no actions! look:-a person has commented a year ago but?NO RESPONSE

Ans 19:

Class : Class 9
they didnt give the options