Practice problems on JEE Mains, JEE Mains 2021 July 25 Shift 2

Question 1

Which one of the following metals forms interstitial hydride easily ?

Accepted Answer

Cr

Answer

Fe

Answer

Co

Answer

Mn

Question 2

Consider the statement "The match will be played only if the weather is good and ground is not wet". Select the correct negation from the following :

Accepted Answer

The match will not be played and weather is not good and around is wet

Answer

The match will be played and weather is not good or ground is wet

Answer

The match will not be played or weather is good and ground is not wet

Answer

If the match will not be played, then either weather is not good or ground is wet

Question 3

A biodegradable polyamide can be made from :

Accepted Answer

Glycine and aminocaproic acid

Answer

Glycine and isoprene

Answer

Styrene and caproic acid

Answer

Hexamethylene diamine and adipic acid

Question 4

Match List I with List II : (Both having metallurgical terms)Choose the correct answer from the options given below

Accepted Answer

(a) - (iii), (b) - (ii), (c) - (i), (d) - (iv)

Answer

(a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)

Answer

(a) - (iv), (b) - (iii), (c) - (ii), (d) - (i)

Answer

(a) - (iv), (b) - (i), (c) - (iii), (d) - (ii)

Question 5

Consider functions f:A→B and g:B→C(A,B,C⊆R) such that (gof) −1 exists, then:

Accepted Answer

f is one-one and g is onto

Answer

f is onto and g is one-one

Answer

f and g both are onto

Answer

f and g both are one-one

Question 6

The lowest integer which is greater than (1+101001​)10100 is

Accepted Answer

3

Answer

4

Answer

1

Answer

2

Question 7

If the greatest value of the term independent of ' x ' in the expansion of (xsinα+axcosα​)10 is (5!)210!​ , then the value of 'a ' is equal to :

Accepted Answer

2

Answer

1

Answer

-1

Answer

-2

Question 8

The sum of all those terms which are rational numbers in the expansion of (231​+341​)12 is :

Accepted Answer

43

Answer

89

Answer

27

Answer

35

Question 9

Let the equation of the pair of lines, y=px and y=qx , can be written as (y−px)(y−qx)=0 . Then the equation of the pair of the angle bisectors of the lines x2−4xy−5y2=0 is:

Accepted Answer

x2+3xy−y2=0

Answer

x2+4xy−y2=0

Answer

x2−3xy−y2=0

Answer

x2+3xy+y2=0

Question 10

The force is given in terms of time t and displacement x by the equationF=AcosBx+CsinDt The dimensional formula of BAD​ is:

Accepted Answer

[ML' T−3 ]

Answer

[M2 L2 T−3]

Answer

[M∘LT−1]

Answer

[M'L'T-2]

Question 11

The correct decreasing order of densities of the following compounds:

Accepted Answer

(D) > (C) > (B) > (A)

Answer

(C) > (B) > (A) > (D)

Answer

(A) > (B) > (C) > (D)

Answer

(C) > (D) > (A) > (B)

Question 12

An electron moving with speed v and a photon moving with speed c, have same D-Broglie wavelength. The ratio of kinetic energy of electron to that of photon is:

Accepted Answer

2cv​

Answer

3cv​

Answer

v3c​

Answer

v2c​

Question 13

The first of the two samples in a group has 100 items with mean 15 and standard deviation 3 . If the whole group has 250 items with mean 15.6 and standard deviation 13.44​ , then the standard deviation of the second sample is:

Accepted Answer

4

Answer

6

Answer

5

Answer

8

Question 14

Which one of the following metal complexes is most stable ?

Accepted Answer

[Co(en)3​]Cl2​

Answer

[Co(en)2​(NH3​)2​]Cl2​

Answer

[Co(NH3​)6​]Cl2​

Answer

[Co(en)2​,(NH3​)4​]Cl2​

Question 15

The instantaneous velocity of a particle moving in a straight line is given as v=αt+βt2 , where α and β are constants. The distance travelled by the particle between 1 s and 2 s is:

Accepted Answer

23​α+37​β

Answer

2α​+3β​

Answer

23​α+27​β

Answer

3α+7β

Question 16

If ∣a∣=2,∣b∣=5 and ∣a×b∣=8, then ∣a⋅b∣ is equal to:

Accepted Answer

6

Answer

5

Answer

4

Answer

3