JEE Mains 2020 January session is almost over now, the JEE main 2020 exam was conducted from January 7th to January 9th in 6 shifts. The last paper of JEE Main was conducted today January 9 in two shifts. First shift timings were 9:30 am to 12:30 pm and second shift timings were 2:30 pm to 5:30 pm. In this article, you will get JEE main 2020 question paper with solution (Jan 9th Second shift). As we all know that NTA is conducting JEE main 2020 exam, this time paper has been more balanced and providing an equal chance to all aspirants. The JEE mains 2020 Jan 9 second shift exam solutions are created by experts on the basis of memory-based JEE mains question available from aspirants. Stay tuned with us for more updates and solutions.

Exam date and Shift | Article URL |
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7th Jan 2020 - Shift 1 | Click here |

7th Jan 2020 - Shift 2 | Click here |

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8th Jan 2020 - Shift 2 | Click here |

9th Jan 2020 - Shift 1 | Click here |

9th Jan 2020 - Shift 2 | Click here |

**Q1) ****In which compound C–Cl bond length is shortest?**

**(1) Cl–CH=CH _{2} **

**(2) Cl–CH=CH–CH _{3} **

**(3) Cl–CH=CH–OCH _{3} **

**(4) Cl–CH=CH–NO _{2}**

**Solution**

Resonance form of Cl–CH=CH–NO_{2} is more stable than resonance form of any other given compounds. Hence, double bond character in carbon-chlorine bond is maximum and bond length is shortest.

Option 4 is correct.

**Q2) Amongst the following which has minimum conductivity.**

**(1) Distilled water **

**(2) Sea water**

**(3) Saline water used for intra venous injection **

**(4) Well-water**

**Solution**

Distilled water is de-ionised water.

option (1) is correct.

**Q3) Number of sp ^{2} hybrid orbitals in a molecule of benzene.**

**1. 6**

**2. 12**

**3. 18**

**4. 24**

**Solution:** 18 sp^{2} hybrid orbitals are present in a molecule of benzene.

Therefore, the option number (3) is correct.

**Q4) Biochemical oxygen demand (BOD) is defined as _______ in ppm of O2.
(1) Required to sustain life
(2) The amount of oxygen required by bacteria to break down the organic matter present in a certain volume of a sample of water.
(3) The amount of oxygen required by anaerobic bacteria to break down the inorganic matter present in a certain volume of a sample of water.
(4) Required photochemical reaction to degrade waste**

**Solution**

The amount of oxygen required by bacteria to break down the organic matter present in a certain volume of a sample of water, is called Biochemical Oxygen Demand (BOD).

Option 2 is correct.

**Q5) Which of the following reaction will not form racemic mixture as product?**

**Solution**

Opton 2 is correct.

**Q6)
Percentage carbon in compound A is:**

**Solution
**

Compounds is:

**Q7) 0.1 ml of an ideal gas has volume 1 dm ^{3} in a locked box with frictionless piston. The gas is in thermal equilibrium with excess of 0.5 m aqueous ethylene glycol at its freezing point. If the piston is released all of a sudden at 1 atm then determine the final volume of gas in dm^{3} (R = 0.08 atm L mol^{–1} K^{–1} K_{f} = 2.0 K molal^{–1}).**

**Solution**

After releasing piston P_{1}V_{1} = P_{2}V_{2}

2.176 x 1 = 1 x V_{2}

V_{2} = 2.176 dm^{3}

**Q8) One litre sea water (d = 1.03g/cm ^{3}) contains 10.3 mg O_{2} gas. Determine concentration of O_{2} in ppm.**

**Solution**

Thus, **the correct answer is 10.**

**Q9) ****Lacto bacillus has generation time 60 min. at 300 K and 40 min. at 400 K. Determine activation energy in mol kJ/mol. (R = 8.3 J K ^{–1}mol^{–1}) [ln(2/3) = -0.4].**

**Solution**

ln(3/2) × 8.3 × 1200 = Ea

E_{a} = 0.4 × 8.3 × 1200

E_{a} = 3984 J/mol.

E_{a} = 3.984 kJ/mol

Thus, **the correct answer is 3.98**

**Q10) Total number of Cr–O bonds in Chromate ion and dichromate ion is:**

**Solution
**

Total number of Cr and O bonds is 12.

**Q11)
**

**Solution
**

**Q12)
Compound A will be:
**

**Solution
**

**Q13) The order of basic character is :**

**(1) I > II > III > IV
(2) IV > III > I > II
(3) II > I > III > IV
(4) IV > I > II > III**

**Solution**

Basic strength depends upon availability of lone pairs. Greater the resonance of lone pairs lesser the basic strength.

Option 2 is correct.

**Q14)
**

**Solution**

Laboratory Test | Molisch's test | Barfoed test |
Biuret test |

Yes | Lactose, Glucose, Fructose | Glucose |
Albumin |

No | Sucrose |
Alanine |

Therefore, Option(1) is correct.

**Q15) 1. 5 g of Zn reacts with
(I) Excess of NaOH (II) Dilute HCl, then volume ratio of H2 gas evolved in (I) and (II) is
(1) 2 : 1 **

**(2) 1 : 2 **

**(3) 1 : 1 **

**(4) 3 : 1**

**Solution**

According to stoichiometry in both the reactions, equal number of moles of H_{2} are evolved.

Option 3 is correct.

**Q16) Given K _{sp} for Cr(OH)_{3} is 6 × 10^{–31} then determine [OH^{–}].**

(Neglect the contribution of OH^{– }ions from H_{2}O)

**Solution**

s 3s

Option 1 is correct.

**Q17) Select the correct statements among the followings
(A) LiCl does not dissolve in pyridine
(B) Li does not react ethyne to form ethynide.
(C) Li and Mg react slowly with water.
(D) Among alkali metals Li has highest hydration tendency.**

**Solution**

Concept Based

Option 1 is correct.

**Q18) Given an element having following ionisation enthalpies IE1 = 496 kJ/mol and IE2 = 4562 kJ/mol one mole hydroxide of this element is treated separated with HCl and H _{2}SO_{4} respectively. Moles of HCl and H_{2}SO_{4} reacted respectively is**

**(1) 1, 0.5 **

**(2) 0.5, 1 **

**(3) 2, 0.5 **

**(4) 0.5, 2**

**Solution**

According to the given data of I.E, This element must belong to group 1 and thus is monovalent & form

hydroxide of the type M(OH).

**Q19) Reactant A represented by square is in equilibrium with product B represented by circles. Then value of
equilibrium constant is**

**(1) 1 **

**(2) 2 **

**(3) 3 **

**(4) 4**

**Solution**

Option 2 is correct.

**Q20) Given following complexes**

**(I) Na _{4}[Fe(CN)_{6}] (II) [Cr(H_{2}O)_{6}] Cl_{2}**

**(III) (NEt _{4})_{2} [CoCl_{4}] (IV) Na_{3}[Fe(C_{2}O_{4})_{3}] **

**Correct order of spin only magnetic moment for the above complexes is.**

**(1) (II) > (III) > (IV) > I **

**(2) (II) > (IV) > (III) > (I)**

**(3) (I) > (IV) > (III) > (II)**

**(4) (II) > (I) > (IV) > (III)**

**Solution**

Option 1 is correct.

**Q21) Select the correct option :
(1) Entropy is function of temperature and also entropy change is function of temperature.
(2) Entropy is a function of temperature & entropy change is not a function of temperature.
(3) Entropy is not a function of temperature & entropy change is a function of temperature.
(4) Both entropy & entropy change are not a function of temperature.**

**Solution**

Option 1 is correct.

**Q22) A compound (A ; B _{3}N_{3}H_{3}Cl_{3}) reacts with LiBH_{4} to form inorganic benzene (B). (A) reacts with (C) to form B_{3}N_{3}H_{3}(CH_{3})_{3}. (B) and (C) are respectively.**

(1) Boron nitride, MeMgBr

**(2) Boron nitride, MeBr**

**(3) Borazine, MeBr **

**(4) Borazine, MeMgBr**

**Solution**

Option 4 is correct.

**Q23) In a box a mixture containing H2, O2 and CO along with charcoal is present then variation of pressure with the time will be as follows :**

**Solution**

Concept based

Option 3 is correct

**Q24) Given complex [Co(NH _{3})_{4}Cl_{2}]. In it if Cl - Co-Cl bond angle is 90º then it is :**

(1) Cis-isomer

**(2) Trans- isomers**

**(3) Meridional and trans **

**(4) Cis and trans both**

**Solution**

Option 1 is correct.

**Q25) Monomer(s) of which of the given polymer is chiral?**

**(1) Buna-S **

**(2) Neoprene **

**(3) Nylon-6,6 **

**(4) PHBV**

**Solution**

In PHBV, both monomers have chiral centre.

Option 4 is correct.

**Q1. AB is focal chord at parabola , where then equation ale tangent at B is**

**Sol**ution:

**Q2. IF and **

**Sol**ution:

Use

**Q3. If the statement is false then p and q respectively is ?**

**Solution:**

**Q4. If , y(1) = 1 and y(x) = e, then x is **

**Solution:**

**Q5. If the minimum value of term free from x for is L _{1 } and L_{2} in. Find .**

**Solution:**

**Q6. Number of common terms in both sequence 3, 7, 11, ………….407 and 2, 9, 16, ……..905 is**

**Solution:
**

**Q7. Let a angle between equal to If is perpendicular to then find the value of .**

**Solution:**

**Q8. Let circles (x – 0) ^{2} + (y – 4)^{2} = k and (x – 3)^{2} + (y – 0)^{2} = 12 touches each other than find the maximum value of 'k'**

**Solution:**

Two circles touch each other if

Distance between C2(3, 0) and C1(0, 4) is either

Also

Maximum value of K is 36

**Q9. **

**Solution:**

**Q10. Let the distance between plane passing through lines and and plane 23x – 10y – 2z + 48 = 0 is then k is equal to**

**Solution:**

** and **

Lines must be intersecting

Hence points are (-3,-2,1)

The distance of plane contains given lines from given plane is same as distance between point (–3, –2,1) from given plane.

Required distance equal to

**Q11. then find the area bounded by f(x) and g(x) from **

**Solution:**

Required area = Area of trapezium ABCD -

**Q12. z is a complex number such that |Re(z)| + |Im (z)| = 4 then |z| can't be**

**Solution:**

z = x + iy

|x| + |y| = 4

Minimum value of |z| =

Maximum value of |z| = 4

So |z| can't be

**Q13. If f(x) = and a – 2b + c = 1, than**

**(1) f(50) = 1**

**(2) f(–50) = – 1**

**(3) f(50) = 501**

**(4) f(50) = – 501 **

**Solution:**

**Q14. Let a _{n} is a positive term of a GP and **

**Solution:**

From above, r = 2

add both

**Q15. Let probability distribution is**

**then value of p(x > 2) is**

**Solution:**

**Q16. Let and then**

**Q17. Let both root of equation ax ^{2} – 2bx + 5 = 0 are and root of equation x^{2} – 2bx – 10 = 0 are and . Find the value of **

**Solution:**

ax^{2} – 2bx + 5 = 0 having equal roots or and

Put in the second equation

**Q18. then correct choice is**

**(1) F(x) has local minimum at x = 1 **

**(2) F(x) has local maximum at x = 1 **

**(3) F(x) has point of inflection at x = 1 **

**(4) F(x) has no critical point**

**Solution:**

**Q19. **Let and find at

**Solution:**

**Q20. If 7x + 6y – 2z = 0; 3x + 4y + 2z = 0 and x – 2y – 6z = 0 then which option is correct**

**(1) no. solution **

**(2) only trivial solution **

**(3) Infinite non trivial solution for x = 2z **

**(4) Infinite non trivial solution for y = 2z**

**Solution:**

so infinite non-trivial solution exist

**Q21. then ordered pair is**

**Solution:**

**Q22. If = A then the value of x at which is discontinuous (where [.] denotes greatest integer function)**

**Solution:**

**Q23. Let x + 6y = 8 is tangent to standard ellipse where the minor axis is , then eccentricity of an ellipse is**

**Solution:**

**Q24. If f(x) and g(x) are continuous functions, fog is identity function, g'(b) = 5 and g(b) = a then f'(a) is**

**Solution:**

** Q-1**

**A mass m attached to spring of natural length and spring constant k. One end of string is attached to centre of disc in horizontal plane which is being rotated by constant angular speed . Find extension per unit length in spring (given )**

**Solution-**

As natural lentgh=l_{0}

Let elongation=x

Mass m is moving with angular velocity in a radius r

where

Due to elongation x spring force is given by

And

as

So

using

So

**Q-2**

**A loop of radius R and mass m is placed in a uniform magnetic field B with its plane perpendicular to the field. Current I is flowing in it. Now loop is slightly rotated about its diameter and released. Find time period of oscillation**

**Solution-**

**Q-3**

**A string of mass per unit length is fixed at both ends under the tension 540 N. If the string is in resonance with consecutive frequencies 420 Hz and 490 Hz. Then find the length of the string?**

**(1) 2.1 m (2) 1.1 m (3) 4.8 m (4) 4.2 m**

**Solution-**

Fundamental frequency = 490 – 420 = 70 Hz

**Q-4**

** **

**Solution:-**

**Q-5**

** **

**Solution:-**

**Q-6**

** **

**Solution:-**

**Q-7**

** **

**Solution:-**

**Q-8**

** **

**Solution:-**

**Q-9**

** **

**Solution:-**

**Q-10**

** **

**Solution:-**

So

**Q-11 **

**Find the current supplied by the battery**

**(1) 0.1 A (2) 0.3 A (3) 0.4 A (4) 0.5 A**

**Solution-**

Both diodes are in reverse biased

So new circuits can be drawn as

So

**Q-12**

**An AC source is connected to the LC series circuit with V = 10 sin (314t). Find the current in the circuit as a function of time? (L = 40 mH, C = 100 F)**

**(1) 10 sin (314t) (2) 5.2 sin (314t) (3) 0.52 sin (314t) (4) 0.52 cos (314t)**

**Solution-**

As

But R=0

**Q-13**

** **

**Solution:-**

**Q-14**

** **

**Solution:-**

**Q-15**

** **

**Solution:-**

**Q-16 **

**An EM wave is travelling in direction. Axis of polarization of EM wave is found to be . Then equation of magnetic field will be -**

** **

**Solution -**

EM wave is in direction -

As we know that the axis of polarisation of the Em wave is same as Electric field direction that is -

direction of propagation of EM wave =

And the equation of the electromagnetic waves will be in terms of the

So by concluding the above result we can deduce that the option (2) is correct.

**Q-17**

**Different value of a, b and c are given and their sum is d. Arrange the value of d in increasing order -**

** **

**Solution -**

So the option (3) is correct.

**Q-18**

**Two gases Ar (40) and Xe (131) at same temperature have same number density. Their diameters are 0.07 nm and 0.10 nm respectively. Find the ratio of their mean free time **

** (1) 1.03 (2) 2.04 (3) 3.04 (4) 2.40**

**Solution -**

So the option (2) is correct.

**Q-19**

**A particle start moving with velocity from origin and acceleration .when y co-ordinate of particle is 32 m. then x co-ordinate at that instant will be**

**(1) 48 (2) 60 (3) 12 (4) 24**

**Solution-**

**Q.20 **

**An electron (-|e|, m) is released in Electric field E from rest. rate of change of de-Broglie wavelength with time will be.**

** **

**Sol.**

**Q.21.**

**In YDSE pattern with light of wavelength , 15 fringes are obtained on a certain segment of**

**screen. If number of fringes for light of wavelength on same segment of screen is 10, then the value
of is-**

**Solution-**

.

**Q.22**

** If in a meter bridge experiment, the balancing length was 25 cm for the situation shown in the figure. If the length and diameter of the of wire of resistance R is made half, then find the new balancing length in centimetre is**

**Sol.**

**Q.23 **

**Find the power loss in each diode (in mW), if potential drop across the zener diode is 8V. **

**Sol.**

**Q.24 **

**An ideal gas at initial temperature 300 K is compressed adiabatically of its initial volume. The gas is then expanded isobarically to double its volume. Then final temperature of gas round to nearest integer is: **

**Sol.**

= constant

= constant

Now for BC process BC

**Q.25 **

**If electric field in the space is given by , and electric flux through ABCD is and
electric flux through BCEF is then find . **

**Sol.**

Flux via ABCD

Flux via BCEF

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