JEE Mains Previous Years Questions with Solutions Android App

Download our App

JEE Mains Previous Years Questions with Solutions

4.5 
star star star star star
  (100k+ download)
1

AIEEE 2006

MCQ (Single Correct Answer)
Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10-31 kg) moving with a velocity 300 ms-1, accurate upto 0.001% will be (h = 6.63 $$\times$$ 10-34 Js)
A
1.92 $$\times$$ 10-2 m
B
3.84 $$\times$$ 10-2 m
C
19.2 $$\times$$ 10-2 m
D
5.76 $$\times$$ 10-2 m

Explanation

% error in velocity = $${{\Delta V} \over V} \times 100$$

$$ \therefore $$ 0.001 = $${{\Delta V} \over {300}} \times 100$$

$$ \Rightarrow $$ $$\Delta $$V = 3 $$ \times $$ 10-3

According to Heisenberg uncertainty principle,

$$\Delta x.m\Delta V \ge {h \over {4\pi }}$$

$$ \Rightarrow $$ $$\Delta x = {h \over {4\pi m\Delta V}}$$

$$ \Rightarrow $$ $$\Delta x = {{6.63 \times {{10}^{ - 34}}} \over {4 \times 3.14 \times 9.1 \times {{10}^{ - 31}} \times 3 \times {{10}^{ - 3}}}}$$

             = 1.92 $$ \times $$ 10-2 m
2

AIEEE 2006

MCQ (Single Correct Answer)
According to Bohr's theory, the angular momentum of an electron in 5th orbit is
A
10 $$h/\pi$$
B
2.5 $$h/\pi$$
C
25 $$h/\pi$$
D
1.0 $$h/\pi$$

Explanation

Formula of angular momentum of an electron,

mvr = $${{nh} \over {2\pi }}$$

here n = 5

$$\therefore$$ mvr = $${{5h} \over {2\pi }}$$ = 2.5$${{h} \over {\pi }}$$
3

AIEEE 2005

MCQ (Single Correct Answer)
Pick out the isoelectronic structure from the following :

$$\eqalign{ & \left( i \right)\,\,\,\,\,\,C{H_3}^ + \cr & \left( {ii} \right)\,\,\,\,{H_3}{O^ + } \cr & \left( {iii} \right)\,\,\,N{H_3} \cr & \left( {iv} \right)\,\,\,\,C{H_3}^ - \cr} $$
A
$$(i)$$ and $$(ii)$$
B
$$(iii)$$ and $$(iv)$$
C
$$(i)$$ and $$(iii)$$
D
$$(ii), (iii)$$ and $$(iv)$$

Explanation

Ions No. of electrons
CH3+ 8
H3O+ 10
NH3 10
CH3- 10


$$\therefore$$ $$\,\,\,$$ $${H_3}{O^ + },N{H_3}$$ and $$C{H_3}^ - $$ are isoelectronic.
4

AIEEE 2005

MCQ (Single Correct Answer)
In a multi-electron atom, which of the following orbitals described by the three quantum members will have the same energy in the absence of magnetic and electric fields?
(A) n = 1, l = 0, m = 0
(B) n = 2, l = 0, m = 0
(C) n = 2, l = 1, m = 1
(D) n = 3, l = 2, m = 1
(E) n = 3, l = 2, m = 0
A
(D) and (E)
B
(C) and (D)
C
(B) and (C)
D
(A) and (B)

Explanation

As here is no electric and magnetic field so ignore m to calculate the energy of orbital.

As here atom is multi-electron so ( n + l ) rule is applicable here. This rule says those orbitals which have more value of ( n + l ) will have more energy.

In (A), n + l = 1 + 0 = 1

In (B), n + l = 2 + 0 = 2

In (C), n + l = 2 + 1 = 3

In (D), n + l = 3 + 2 = 5

In (E), n + l = 3 + 2 = 5

So (D) and (E) will be of equal energy.

Questions Asked from Structure of Atom

On those following papers in MCQ (Single Correct Answer)
Number in Brackets after Paper Indicates No. of Questions
JEE Main 2021 (Online) 26th August Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 27th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 27th July Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 20th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 18th March Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 18th March Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 17th March Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 26th February Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 26th February Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th February Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 24th February Evening Shift (1)
keyboard_arrow_right
JEE Main 2020 (Online) 5th September Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 5th September Morning Slot (3)
keyboard_arrow_right
JEE Main 2020 (Online) 4th September Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 4th September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 2nd September Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 2nd September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 9th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 8th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 8th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 7th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 12th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 10th April Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 10th April Morning Slot (3)
keyboard_arrow_right
JEE Main 2019 (Online) 9th April Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 8th April Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 8th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 12th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 12th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 11th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 11th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 10th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 9th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 9th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2018 (Online) 16th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2018 (Online) 15th April Evening Slot (1)
keyboard_arrow_right
JEE Main 2018 (Online) 15th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2017 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2017 (Online) 8th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2017 (Offline) (2)
keyboard_arrow_right
JEE Main 2016 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2016 (Offline) (1)
keyboard_arrow_right
JEE Main 2015 (Offline) (1)
keyboard_arrow_right
JEE Main 2014 (Offline) (1)
keyboard_arrow_right
JEE Main 2013 (Offline) (1)
keyboard_arrow_right
AIEEE 2012 (1)
keyboard_arrow_right
AIEEE 2011 (1)
keyboard_arrow_right
AIEEE 2010 (2)
keyboard_arrow_right
AIEEE 2009 (2)
keyboard_arrow_right
AIEEE 2008 (2)
keyboard_arrow_right
AIEEE 2007 (1)
keyboard_arrow_right
AIEEE 2006 (3)
keyboard_arrow_right
AIEEE 2005 (3)
keyboard_arrow_right
AIEEE 2004 (4)
keyboard_arrow_right
AIEEE 2003 (5)
keyboard_arrow_right
AIEEE 2002 (2)
keyboard_arrow_right

Joint Entrance Examination

JEE Advanced JEE Main

Graduate Aptitude Test in Engineering

GATE CSE GATE ECE GATE ME GATE PI GATE EE GATE CE GATE IN

Medical

NEET

CBSE

Class 12