National Science Olympiad Forum By SOF Olympiad Trainer - Page 254

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Subject :NSO    Class : Class 10

A small conducting rod of length l, moves with a uniform velocity v in a uniform magnetic field B as shown in figure.


A The end X of the rod becomes positively charged.
B The end Y of the rod becomes positively charged.
C The entire rod is unerringly charged.
D The rod becomes hot due to joule heating.


By Fleming's right-hand rule, current flows from X to Y, but which end actually receives the extra positive charge?

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Subject :NSO    Class : Class 6

Ans 1:

Class : Class 6
See, Y is feeding on x which means that population of X would definitely decrease. This means that eater of water beetle has decreased. This indicates that population of water beetle will increase. This means more food for fro with beetle. with g. Due to large amount of food frogs' population will also increase parallelly. In this way B would be correct . Sorry for too long answer.

Ans 2:

Class : Class 8

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Subject :NSO    Class : Class 6

Ans 1:

Class : Class 7

Ans 2:

Class : Class 7
C

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Subject :NSO    Class : Class 7

Two containers X and Y are filled with equal amount of hot water and the temperature of the water in the containers is measured with a thermometer some time later. It is observed that container X has a much lower temperature than container Y. Which of the following are the possible reasons?
(i) Container X is black and container Y is silver.
(ii) Container X has a lid and container Y is not covered.
(iii) Container X is made of steel and container Y is made of clay.

A(i) and (ii) only
B(i) and (iii) only
C(ii) and (iii) only
D(i), (ii) and (iii)


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Subject :NSO    Class : Class 8

Ans 1:

Class : Class 8
it should be b because they have asked in the increasing order

Ans 2:

Class : Class 8
The question asks the increasing order.. answer is B

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Subject :NSO    Class : Class 3

Ans 1:

Class : Class 7

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Subject :NSO    Class : Class 6

Properties of a few substances are given as :
P : White solid, soluble in water, non-magnetic in nature, salty in taste
Q : Blue solid, insoluble in water, non-magnetic in nature, sweet in taste
R : White solid, soluble in water, non-magnetic in nature, sweet in taste
S : Black solid, magnetic in nature, insoluble in water
Read the given passage and fill in the blanks by selecting an appropriate option.
Substances __(i)__ when present in a mixture can be separated from each other by filtration or magnetic separation, substances __(ii)__ can be separated by magnetic separation only, while substances __(iii)__ when mixed in water are very difficult to separate by common methods of separation.

  (i) (ii) (iii)
A Q, R P, S Q, S
B P, S Q, S P, R
C P, S P, R Q, R
D Q, S P, R Q, P


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Subject :NSO    Class : Class 1

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Subject :NSO    Class : Class 7

Ans 1:

Class : Class 8

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Subject :NSO    Class : Class 3

Ans 1: (Master Answer)

Class : Class 1

D

Safety tool used while horse riding - Helmet, House built by Eskimos - Igloo, A group of stars forming a recognizable pattern in sky, named dafter a hunter in Greek mythology - Orion, A tunnel or passage built under a road for use by pedestrians – Underpass
Helmet, Igloo and Orion can be found on the word-grid, but not Underpass. Hence, Option D is the right answer.


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