1
JEE Main 2019 (Online) 12th April Evening Slot
+4
-1
A small speaker delivers 2 W of audio output. At what distance from the speaker will one detect 120 dB intensity sound ? [Given reference intensity of sound as 10–12 W/m2 ]
A
20 cm
B
10 cm
C
40 cm
D
30 cm
2
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
A progressive wave travelling along the positive x-direction is represented by y(x,t) = Asin(kx – $$\omega$$t + $$\phi$$). Its snapshot at t = 0 is given in the figure.
For this wave, the phase $$\phi$$ is :
A
$${\pi \over 2}$$
B
$$\pi$$
C
0
D
$$- {\pi \over 2}$$
3
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
Out of Syllabus
A submarine (A) travelling at 18 km/hr is being chased along the line of its velocity by another submarine (B) travelling at 27 km/hr. B sends a sonar signal of 500 Hz to detect A and receives a reflected sound of frequency $$\upsilon$$. The value of $$\upsilon$$ is close to: (Speed of sound in water =1500 ms–1)
A
507 Hz
B
502 Hz
C
499 Hz
D
504 Hz
4
JEE Main 2019 (Online) 10th April Evening Slot
+4
-1
The correct figure that shows, schematically, the wave pattern produced by superposition of two waves of frequencies 9 Hz and 11 Hz, is :
A
B
C
D
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