1
JEE Main 2020 (Online) 6th September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
In the figure below, P and Q are two equally intense coherent sources emitting radiation of wavelength 20 m. The separation between P and Q is 5 m and the phase of P is ahead of that of Q by 90o. A, B and C are three distinct points of observation, each equidistant from the midpoint of PQ. The intensities of radiation at A, B, C will be in the ratio :

JEE Main 2020 (Online) 6th September Morning Slot Physics - Wave Optics Question 78 English
A
4 : 1 : 0
B
2 : 1 : 0
C
0 : 1 : 2
D
0 : 1 : 4
2
JEE Main 2020 (Online) 5th September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Two coherent sources of sound, S1 and S2, produce sound waves of the same wavelength, $$\lambda $$ = 1 m, in phase. S1 and S2 are placed 1.5 m apart (see fig). A listener, located at L, directly in front of S2 finds that the intensity is at a minimum
when he is 2 m away from S2. The listener moves away from S1, keeping his distance from S2 fixed. The adjacent maximum of intensity is observed when the listener is at a distance d from S1. Then, d is : JEE Main 2020 (Online) 5th September Evening Slot Physics - Wave Optics Question 79 English
A
12 m
B
2 m
C
3 m
D
5 m
3
JEE Main 2020 (Online) 4th September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A beam of plane polarised light of large
cross-sectional area and uniform intensity
of 3.3 Wm-2 falls normally on a
polariser (cross sectional area 3 $$ \times $$ 10-4 m2) which
rotates about its axis with an angular speed
of 31.4 rad/s. The energy of light passing through
the polariser per revolution, is close to :
A
1.0 $$ \times $$ 10-5 J
B
1.0 $$ \times $$ 10-4 J
C
1.5 $$ \times $$ 10-4 J
D
5.0 $$ \times $$ 10-4 J
4
JEE Main 2020 (Online) 3rd September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Two light waves having the same wavelength $$\lambda $$ in vacuum are in phase initially. Then the first wave travels a path L1 through a medium of refractive index n1 while the second wave travels a path of length L2 through a medium of refractive index n2 . After this the phase difference between the two waves is :
A
$${{2\pi } \over \lambda }\left( {{n_1}{L_1} - {n_2}{L_2}} \right)$$
B
$${{2\pi } \over \lambda }\left( {{n_2}{L_1} - {n_1}{L_2}} \right)$$
C
$${{2\pi } \over \lambda }\left( {{{{L_1}} \over {{n_1}}} - {{{L_2}} \over {{n_2}}}} \right)$$
D
$${{2\pi } \over \lambda }\left( {{{{L_2}} \over {{n_1}}} - {{{L_1}} \over {{n_2}}}} \right)$$
JEE Main Subjects
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
CBSE
Class 12