1
JEE Main 2020 (Online) 4th September Evening Slot
+4
-1
Out of Syllabus
The driver of a bus approaching a big wall notices that the frequency of his bus's horn changes from 420 Hz to 490 Hz when he hears it after it gets reflected from the wall. Find the speed of the bus if speed of the sound is 330 ms–1.
A
91 kmh–1
B
81 kmh–1
C
61 kmh–1
D
71 kmh–1
2
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
For a transverse wave travelling along a straight line, the distance between two peaks (crests) is 5 m, while the distance between one crest and one trough is 1.5 m. The possible wavelengths (in m) of the are :
A
1, 3, 5, .....
B
$${1 \over 1},{1 \over 3},{1 \over 5},$$ .....
C
1, 2, 3, .....
D
$${1 \over 2},{1 \over 4},{1 \over 6},$$
3
JEE Main 2020 (Online) 3rd September Morning Slot
+4
-1
A uniform thin rope of length 12 m and mass 6 kg hangs vertically from a rigid support and a block of mass 2 kg is attached to its free end. A transverse short wavetrain of wavelength 6 cm is produced at the lower end of the rope. What is the wavelength of the wavetrain (in cm) when it reaches the top of the rope ?
A
12
B
3
C
9
D
6
4
JEE Main 2020 (Online) 2nd September Morning Slot
+4
-1
Two identical strings X and Z made of same material have tension TX and TZ in them. If their fundamental frequencies are 450 Hz and 300 Hz, respectively, then the ratio TX/TZ is
A
2.25
B
0.44
C
1.25
D
1.5
EXAM MAP
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