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RAO IIT ACADEMY / NSEJS / Code-JS512 / Solutions

National Standard Examination in Junior Science (NSEJS)

Date: 18 Nov 2018

1.

Di�iculty : Medium

Topics :

Biodiversity,

Archaeabacteria divided by binary fission or fragmentation, or by budding. Some of the archaeabacteria flagella.

They also have ether lipids in cell membranes.

They also have peptidoglycans in their cell wall.

2.


Topics :

Biodiversity,

Platyhelminthis or flatworms have a blind sac body plan and thus are not eucoelomates.

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Solutions

1


3.


Topics :

CELL,

Acrosome vesicle is derived from the golgi apparatus during spermiogenisis.

4.


Topics :

Health and Disease,

All are features of acquried immunity.

5.


Topics :

Biology,

For paddy fields azolla and anabena are used.

6.


Topics :

Nervous tissue,

During an anion potential enter the axon while exist the axon, thus the neuron is depolarised.

7. Di�iculty : Medium

Topics :

Genetic Disorders,

Mutant 2 was made to lypase the up, mutant 4 for mutant 2 for the sequence ofaddihired will be (D).

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8.


Topics :

MOLECULAR BASIS OF INHERITANCE ,

as gene code is a triplet.

9.

Di�iculty : Di�icult

Topics :

Human Endocrine System,

Stimulation of anterior lobe of pitutary brings about secretion of TSH - thyroid stimulating hormone which brings aboutsecretion of thyroid hormone which helps in development of frog.

10.


Topics :

Genetic and Heredity,

The color of coat here is an example of dominant epistatis, where oen gene makes the express of outer gene, here full color (C)(gene C) makes chinchilla , which inturn makes Himalayan and Agouti is recesive to all.

So to get all agothi color, we need a resumed phenotype CC, which will only be possible if both parents here C all etc, which isonly in option (C).

Chinchilla : Himalayan : Agout

11.


Topics :

Biodiversity,

Bull shark and Alpine salmander.

Bull shark viviparous (odd)

Alpine salmander viviparous (odd)



12. Di�iculty : Di�icult

Topics :

Health and Disease,

Guanfacine hypercholoride is use in hypertension. It is prescribed with osmotic diuretics

13.


Topics :


According to Charga�'s rule, amount of purine is equal to amount of pyrimidine.

bonds to T and thus A & T will be present in equal amount and universly C and G will be present equally so

T C A G

Strand I 348 X 650 1400

Strand II 650 1400 348 Y

and

Now in 1 standard number of

solving for

and

14.


Topics :

Biotechnology ,

If brinjal was made to compact interaction by balloons (insects).



15.


Topics :


Number of generations

So bacteria will have generations.

In generation bacteria growth

16.


Topics :

Biodiversity,

(P) - has no membrane found cell organelles, thus is a bacteria.

(Q) - has all membrane organelles and also cell wall and chloroplast, thus is a plant.

(R) - Only genetic material is present so it is a virus.

(S) - No cell wall and no chloroplast, all other organelles are present, thus animal.

(T) - No centriole and no chloroplast is present, thus fungi.

17.


Topics :

Genetic Code,

The darkly stained body is that of an extra X chromosome (barr body). For the body to be gain, the parents have to normal andfertile, thus are of and type. The child but su�ers from klinefelter's syndrome.



18.

Di�iculty : Easy

Topics :

Genetic Code,

Using standard rotation

the product of allele

the product of allele

Now in Ramesh enzyme is present and present in the genotype then is

In Ali and both are formed so genotype

In Sophia, only is present at so

19.

Di�iculty : Easy

Topics :

BIODIVERSITY AND CONSERVATION ,

The highest number of endemic plants are present in and also the habitat lost is so, by defination area is willcovered by regetation.

20. Di�iculty : Easy

Topics :


The child of Mary is Jim's. Because both DNA 1 and 5 are present in both Jim and Mary's child, but not in Lou child.

21.

Di�iculty : Easy

Topics :

Thermal expansion,

It's SI unit is



22.


Topics :

Ray Optics,

__________ (i)

__________ (ii)

Total deviation

____________ (iii)

(Using equation (i) and (ii))

Now from

____________ (iv)

From equation (iii) and (iv),



23.


Topics :

Sound wave,

Let and be the wavelengths of the two sound waves where

____________ (i)

The lower pitch sound is corresponding to higher wavelength.

So, it's frequency

Or,

We have (as musical interval is )

from ii,

( is speed of sound)



24.


Topics :

Ray Optics,

magnification

and

Given

(negative sign indicates that mirror is concave)

focal length is



25.


Topics :

Ray Optics,

It will be of the same size for any position of the point source on the line


Topics :

Kinematics,

At time , is at a distance from and at a distance from



27.


Topics :

Kinematics,

Speed of the ball at the instant it touches the ground is given by

here and

For the motion inside the cake, let retardation be

then, we have,

using



28.


Topics :

Work ,Energy and power,

Electric energy generated per second = 25 kJ

heat energy consumed per second

heat energy consumed per hour

mass of the fuel consumed per hour

per kg of fuel burnt, electrical energy generated

for 1 ton of fuel burnt, electrical energy generated



29.


Topics :

Optics,



30.


Topics :

Oscillations and Waves,

Time period of one oscillation

For oscillations,

In Pulse

In Pulse

bradycardia

31.


Topics :

ELECTRICITY,

For integer



32.


Topics :

Fluids,

Let be the volume of block

In case of floatation

...(1)

Let be the volume of block submerged in salt solution

Fraction of volume remains above the salt solution



33.

Di�iculty : Easy

Topics :

Units,Dimensions & Error analysis,

34.


Topics :

HEAT,

A good absorber is good emitter.



35. Di�iculty : Di�icult

Topics :

ELECTRICITY,

of ball

...(i)

and ...(ii)

Now, (1)/(2)

from above expression, increases with decrease in .

will be maximum on Mercury.



36.


Topics :

SOUND,

at



37.


Topics :

ELECTRICITY,

38.

Di�iculty : Easy

Topics :

ELECTRICITY,

(i) Capacitance of hollow sphere = Capacitance of solid sphere,

for hollow and solid sphere, charge would be same.

(ii) A charged body can attract another uncharged body.

(iii) Electric lines of force never intersect.

39.


Topics :

HEAT,

Water has maximum density at so if the water is heated above or cooled below density decreases i.e.,volume increases. In other words, it expands so it overflows in both the cases.



40.


Topics :

MAGNETISM,

In case I & IV

Magnetic moment and magnetic field are antiparallel to each other and this is the condition for maximum potential energy.

41.

Di�iculty : Easy

Topics :

Mole concept,

Ratio of moles of will determine simplest or empirical formula.

42. Di�iculty : Easy

Topics :

Periodic Table,

ratio or nuclear charge w.r.t electrons ratio for is lower than atom.

core electrons or inner shell electrons

experience same shielding force

(Ratio)




Topics :

Liquids and gases,

Surface tension is same on earth and space but the height of capillary column is inversely proportional to gravity, hence waterwill rise along its full length.

44.

Di�iculty : Easy

Topics :

Volumetric analysis,

45.


Topics :


46.

Di�iculty : Easy

Topics :

Gaseous State,



47.


Topics :

Gaseous State,

If is constant, Avogadro's law is applicable

48.


Topics :

Chemistry,Inorganic,

Topic : Sulphur Compounds,

is sparingly soluble in water and forms a weakly dibasic sulphurous acid.

49.


Topics :

STOICHIOMETRY,



50.

Di�iculty : Easy

Topics :

Ionic equilibrium,

Compounds Approx. Nature insolutionNeutral

BasicAcidicAcidic

Bobby who uses increase value to desirable range at it is salt of (strong base + weak acid)

51.


Topics :

Mole concept,

52.


Topics :

Chemical Bonding,

X and Z are s-block elements have tendency to form ionic crystals having high melting point.



53.


Topics :

Stoichiometric Calculations,

54.

Di�iculty : Easy

Topics :


55.


Topics :

Redox reactions,

As per law of conservation of mass,

Mass of Iron used + Mass of = Mass of formed + Mass of (Assume )



56.


Topics :


Solutions (Q) is hydrated acid

(Molar mass = 126 g)

, which is 40 ppm concentration.

57.

Di�iculty : Easy

Topics :

Metallurgy,

Calamine is which is ore of Zinc and not of Aluminium metal.

58.


Topics :

Hydrocarbon,

Higher the octane number, higher must be % by weight of iso-octane to give higher e�iciency of engine which means improvedquality of petrol.

59.


Topics :

Balancing of redox reactions,



60.

Di�iculty : Easy

Topics :

Ionic equilibrium,

solution is a basic solution which is going to turn universal indicator or litmus paper Red litmus Blue.

is a salt of

(Weak acid and Strong acid)



61.


Topics :

Circles,

The required circle is as shown with radius

Note that there are two more circles touching and as shown

with radius

with radius

We do not need to calculate because as it is not the largest radius. However, can be calculated as follows (shouldnot be done in the exam). In the following

We have

Solving for we get

Alternately use Stewart's theorem to get directly.



62.


Topics :

Mathematics,

Topic: Number Theory

Product of any four consecutive integers is divisible by and product of two consecutive numbers isdivisible by two. Hence

The above is always divisible by

63.


Topics :

Permutations & Combinations,

Key: C or D

If a number appeared 3rd time only in the throw In first throws, 5 numbers appeared twice and one numberappeared once. Let the number appeared once be and the number appeared on throw as

Since and

The only possibility is or

Hence the least number appeared could be or

i.e. either he threw once, twice and thrice or

once, twice and thrice.



64.


Topics :

GEOMETRY,

is equilateral

Drop from to

Area of

65.


Topics :


Question does not make sence.

Under some assumption we can form three cuboids of the size which isnot in the option.

The question probably meant how many cuboids can be selected from this cube for which we have cuts in each dimensionsfor every cuboid selected there are cuts required in each dimensions giving for which option D is correct.

66.


Topics :


If has positive divisors, then must be of the form

or where

or

Number of divisors

Here it is assume that is not a multiple of Because if it is, then or or giving number of divisors of

or or as or or Hence is also a possible (but not always an answer)



67.


Topics :

ALGEBRA,

Rationalizing

Now

or

(Here it is assumed that )

Alternately

Applying

or

Applying once again

or

or

* Note that it is assumed for which we get answer as otherwise we will get



68.


Topics :


Let and be no. of sides

no. of diagonals and

and

Subtracting we get

divisor of

and

of which only and satisfies

Note : We calculate number of diagonals of a polygon as follows. Let be no. of sides of polygon. Now for a diagonal, everyvertex can be joined with other vertices. This can be done in ways. But in this every diagonal is counted

twice, giving number of diagonals



69.

Di�iculty : Easy

Topics :

GEOMETRY,

Using ptolemy's theorem in cyclic quadrilateral we get

but

... Note that this is true for any point on minor arc

diameter

Alternately we have equal chords subtend equal angle

as

Now is with

70.

Di�iculty : Easy

Topics :

LINEAR EQUATIONS IN TWO VARIABLES,

and

and

sum of digits



71.

Di�iculty : Easy

Topics :

Sequence & Series,

Now

72.


Topics :

Sequence & Series,GEOMETRY,

in A.P.

Sum of digits of



73.

Di�iculty : Easy

Topics :

Quadratic Equations,

As

74.


Topics :

Mathematics,

Topic : Number Theory

but

Total distinct integers.



75.


Topics :

GEOMETRY,

Take

Now

Note: Here it is assumed that m and n are co prime integers without which any answer is correct. For e.g. consider m=26/11and n=117/11 for which m/n=2/9 and m+n=13.

76.

Di�iculty : Easy

Topics :

Sequence & Series,

...(1)

...(2)

Product of terms =

* It is assumed that



77.


Topics :

Mathematics,


As is divisible by

is divisible by can't be divisible by

or

Now if is divisible by as well

can be anything from possibilities

If then must be divisible by as isn't divisible by

No. of pairs

No option matching

78.


Topics :

GEOMETRY,

Draw parallel from to meeting in

Now let

Alternately, apply Menelau's theorem in with as transversal



79.


Topics :

Mathematics,


and

80.


Topics :

GEOMETRY,

As and have same height and sum of parallel sides, they have same area say

Let

Now


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