1
MCQ (Single Correct Answer)

JEE Main 2018 (Online) 16th April Morning Slot

Unpolarized light of intensity I is incident on a system of two polarizers, A followed by B. The intensity of emergent light is I/2. If a third polarizer C is placed between A and B, the intensity of emergent light is reduced to I/3. The angle between the polarizers A and C is $$\theta $$. Then :
A
cos$$\theta $$ = $${\left( {{2 \over 3}} \right)^{{\raise0.5ex\hbox{$\scriptstyle 1$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 2$}}}}$$
B
cos$$\theta $$ = $${\left( {{2 \over 3}} \right)^{{\raise0.5ex\hbox{$\scriptstyle 1$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 4$}}}}$$
C
cos$$\theta $$ = $${\left( {{1 \over 3}} \right)^{{\raise0.5ex\hbox{$\scriptstyle 1$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 2$}}}}$$
D
cos$$\theta $$ = $${\left( {{1 \over 3}} \right)^{{\raise0.5ex\hbox{$\scriptstyle 1$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 4$}}}}$$
2
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 9th January Morning Slot

A convex lens is put 10 cm from a light source and it makes a sharp image on a screen, kept 10 cm from the lens. Now a glass block (refractive index 1.5) of 1.5 cm thickness is placed in contact with the light source. To get the sharp image again, the screen is shifted by a distance d. Then d is :
A
1.1 cm away from the lens
B
0
C
0.55 cm towards the lens
D
0.55 cm away from the lens

Explanation



Image is formed on the screen.

So, v = 10 cm

and $$\mu $$ = $$-$$ 10 cm

Using formula,

$${1 \over v} - {1 \over u} = {1 \over f}$$

$$ \Rightarrow $$   $${1 \over {10}} - {1 \over {\left( { - 10} \right)}}$$ = $${1 \over f}$$

$$ \Rightarrow $$   f = 5 cm

Now a glass block is placed like this,



Because of this glass block source will move t$$\left( {1 - {1 \over \mu }} \right)$$ in the direction of incident ray.

$$ \therefore $$   S' = t$$\left( {1 - {1 \over \mu }} \right)$$

= 1.5$$\left( {1 - {2 \over 3}} \right)$$

= 0.5

$$ \therefore $$   now distance of source from the lens = 10 $$-$$ 0.5 = 9.5 cm

$$ \therefore $$   $$\mu $$ = $$-$$ 9.5 cm

$$ \therefore $$   $${1 \over v} - {1 \over {\left( { - 9.5} \right)}}$$ = $${1 \over 5}$$

$$ \Rightarrow $$   $${1 \over v}$$ = $${1 \over 5} - {2 \over {19}}$$

$$ \Rightarrow $$   $${1 \over v}$$ = $${9 \over {95}}$$

$$ \Rightarrow $$   v = 10.55 cm

So, to get sharp image screen should shift away (10.55 $$-$$ 10) = 0.55 cm from the lens.
3
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 9th January Morning Slot

Consider a tank made of glass(refractive index 1.5) with a thick bottom. It is filled with a liquid of refractive index $$\mu $$. A student finds that, irrespective of what the incident angle i (see figure) is for a beam of light entering the liquid, the light reflected from the liquid glass interface is never completely polarized. For this to happen, the minimum value of $$\mu $$ is :

A
$$\sqrt {{5 \over 3}} $$
B
$${3 \over {\sqrt 5 }}$$
C
$${5 \over {\sqrt 3 }}$$
D
$${4 \over 3}$$

Explanation



When light is incident on the liquid at 90o, then from ssnells law,

1.sin90o = $$\mu $$sin$$\theta $$

$$ \Rightarrow $$   sin$$\theta $$ = $${1 \over \mu }$$ . . . . . . (1)

Between liquid and glass,

$$\mu $$sin$$\theta $$ = 1.5 sin r

$$ \Rightarrow $$   $$\mu $$sin$$\theta $$ = 1.5 sin (90o $$-$$ $$\theta $$)

$$ \Rightarrow $$   $$\mu $$ tan$$\theta $$ = 1.5

$$ \Rightarrow $$   tan$$\theta $$ = $${{1.5} \over \mu }$$

$$ \therefore $$   sin$$\theta $$ = $${{1.5} \over {\sqrt {{\mu ^2} + {{\left( {1.5} \right)}^2}} }}$$ . . . . . . (2)

$$ \therefore $$    From (1) and (2) we get,

$${1 \over \mu }$$ = $${{1.5} \over {\sqrt {{\mu ^2} + {{\left( {1.5} \right)}^2}} }}$$

$$ \Rightarrow $$   $$\mu $$2 + (1.5)2 = $$\mu $$2 $$ \times $$ (1.5)2

$$ \Rightarrow $$   $$\mu $$ = $${3 \over {\sqrt 5 }}$$
4
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 9th January Evening Slot

In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength $$\lambda $$ = 500 nm is incident on the slits. The total number of bright fringes that are observed in the angular range $$-$$ 30o$$ \le $$$$\theta $$$$ \le $$30o is :
A
640
B
320
C
321
D
641

Explanation



We know, path difference,

d sin$$\theta $$ = n$$\lambda $$

here n = no of bright fringer in the angle

here given

d = 0.32 $$ \times $$ 10-3 m

$$\lambda $$ = 500 $$ \times $$ 10$$-$$9 m

$$ \therefore $$  0.32 $$ \times $$ 10$$-$$3 sin30o = n $$ \times $$ 500 $$ \times $$ 10$$-$$9

$$ \Rightarrow $$  n = 320

Total number of maxima in the range

$$-$$ 30o $$\theta $$ $$ \le $$ 30o is = 320 $$ \times $$ 2 + 1 = 641

Questions Asked from Ray & Wave Optics

On those following papers in MCQ (Single Correct Answer)
Number in Brackets after Paper Name Indicates No of Questions
AIEEE 2002 (5)
keyboard_arrow_right
AIEEE 2003 (3)
keyboard_arrow_right
AIEEE 2004 (5)
keyboard_arrow_right
AIEEE 2005 (6)
keyboard_arrow_right
AIEEE 2006 (1)
keyboard_arrow_right
AIEEE 2007 (2)
keyboard_arrow_right
AIEEE 2008 (1)
keyboard_arrow_right
AIEEE 2009 (2)
keyboard_arrow_right
AIEEE 2010 (3)
keyboard_arrow_right
AIEEE 2011 (3)
keyboard_arrow_right
AIEEE 2012 (3)
keyboard_arrow_right
JEE Main 2013 (Offline) (4)
keyboard_arrow_right
JEE Main 2014 (Offline) (3)
keyboard_arrow_right
JEE Main 2015 (Offline) (3)
keyboard_arrow_right
JEE Main 2016 (Offline) (3)
keyboard_arrow_right
JEE Main 2016 (Online) 9th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2016 (Online) 10th April Morning Slot (3)
keyboard_arrow_right
JEE Main 2017 (Offline) (3)
keyboard_arrow_right
JEE Main 2017 (Online) 8th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2017 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2018 (Offline) (2)
keyboard_arrow_right
JEE Main 2018 (Online) 15th April Morning Slot (3)
keyboard_arrow_right
JEE Main 2018 (Online) 15th April Evening Slot (2)
keyboard_arrow_right
JEE Main 2018 (Online) 16th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 9th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 9th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 10th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 10th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 11th January Morning Slot (3)
keyboard_arrow_right
JEE Main 2019 (Online) 11th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 12th January Morning Slot (3)
keyboard_arrow_right
JEE Main 2019 (Online) 12th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 8th April Morning Slot (3)
keyboard_arrow_right
JEE Main 2019 (Online) 8th April Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 9th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 9th April Evening Slot (3)
keyboard_arrow_right
JEE Main 2019 (Online) 10th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 10th April Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 12th April Morning Slot (3)
keyboard_arrow_right
JEE Main 2019 (Online) 12th April Evening Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 7th January Morning Slot (3)
keyboard_arrow_right
JEE Main 2020 (Online) 7th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 8th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 8th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 9th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 9th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 4th September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 2nd September Morning Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 2nd September Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 3rd September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 3rd September Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 5th September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 6th September Morning Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 6th September Evening Slot (1)
keyboard_arrow_right
JEE Main 2021 (Online) 24th February Morning Slot (2)
keyboard_arrow_right
JEE Main 2021 (Online) 24th February Evening Slot (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th February Morning Slot (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th February Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 26th February Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 26th February Evening Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 16th March Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 16th March Evening Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 17th March Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 18th March Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 18th March Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 20th July Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 20th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 22th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th July Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 25th July Evening Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 27th July Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 27th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 26th August Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 27th August Morning Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 27th August Evening Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 31st August Morning Shift (1)
keyboard_arrow_right

EXAM MAP

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