1
JEE Main 2019 (Online) 12th January Evening Slot
+4
-1
A resonance tube is old and has jagged end. It is still used in the laboratory to determine velocity of sound in air. A tuning fork of frequency 512 Hz produces first resonance when the tube is filled with water to a mark 11 cm below a reference mark, near the open end of the tube. The experiment is repeated with another fork of frequency 256 Hz which produces first resonance when water reaches a mark 27 cm below the reference mark. The velocity of sound in air, obtained in the experiment, is close to :
A
335 ms–1
B
328 ms–1
C
341 ms–1
D
322 ms–1
2
JEE Main 2019 (Online) 12th January Morning Slot
+4
-1
A travelling harmonic wave is represented by the equation y(x,t) = 10–3sin (50t + 2x), where, x and y are in mater and t is in seconds. Which of the following is a correct statement about the wave ?
A
The wave is propagating along the positive x-axis with speed 100 ms–1
B
The wave is propagating along the positive x-axis with speed 25 ms–1
C
The wave is propagating along the negative x-axis with speed 25 ms–1
D
The wave is propagating along the negative x-axis with speed 100 ms–1
3
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
Equation of travelling wave on a stretched string of linear density 5 g/m is y = 0.03 sin(450 t – 9x) where distance and time are measured in SI units. The tension in the string is :
A
10 N
B
7.5 N
C
5 N
D
12.5 N
4
JEE Main 2019 (Online) 10th January Morning Slot
+4
-1
Out of Syllabus
A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is ƒ1. If the speed of the train is reduced to 17 m/s, the frequency registered is ƒ2. If speed of sound is 340 m/s, then the ratio ƒ12 is -
A
19/18
B
20/19
C
21/20
D
18/17
EXAM MAP
Medical
NEET