1
JEE Advanced 2016 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2
Two loudspeakers M and N are located 20m apart and emit sound at frequencies 118 Hz and 121 Hz, respectively. A car in initially at a point P, 1800 m away from the midpoint Q of the line MN and moves towards Q constantly at 60 km/h along the perpendicular bisector of MN. It crosses Q and eventually reaches a point R, 1800 m away from Q.

Let v(t) represent the beat frequency measured by a person sitting in the car at time t. Let vP, vQ and vR be the beat frequencies measured at locations P, Q and R respectively. The speed of sound in air is 330 ms$$-$$1. Which of the following statement(s) is (are) true regarding the sound heard by the person?
A
The plot below represents schematically the variation of beat frequency with time
B
The rate of change in beat frequency is maximum when the car passes through Q
C
vP + vR = 2vQ
D
The plot below represents schematically the variations of beat frequency with time

2
JEE Advanced 2014 Paper 1 Offline
MCQ (More than One Correct Answer)
+3
-0
One end of a taut string of length 3 m along the x-axis is fixed at x = 0. The speed of the waves in the string is 100 ms$$-$$1. The other end of the string is vibrating in the y-direction so that stationary waves are set up in the string. The possible waveform(s) of these stationary wave is (are)
A
$$y(t) = A\sin {{\pi x} \over 6}\cos {{50\pi t} \over 3}$$
B
$$y(t) = A\sin {{\pi x} \over 3}\cos {{100\pi t} \over 3}$$
C
$$y(t) = A\sin {{5\pi x} \over 6}\cos {{250\pi t} \over 3}$$
D
$$y(t) = A\sin {{5\pi x} \over 2}\cos 250\pi t$$
3
JEE Advanced 2014 Paper 1 Offline
MCQ (More than One Correct Answer)
+3
-0
A student is performing an experiment using a resonance column and a tuning fork of frequency 244 s$$-$$1. He is told that the air in the tube has been replaced by another gas (assume that the column remains filled with the gas). If the minimum height at which resonance occurs is (0.350 $$\pm$$ 0.005) m, the gas in the tube is

(Useful information : $$\sqrt {167RT}$$ = 640 J1/2 mol$$-$$1/2; $$\sqrt {140RT}$$ = 590 J1/2 mol$$-$$1/2. The molar mass M in grams is given in the options. Take the values of $$\sqrt {10/M}$$ for each gas as given there.)
A
Neon $$\left( {M = 20,\sqrt {{{10} \over {20}}} = {7 \over {10}}} \right)$$
B
Nitrogen $$\left( {M = 28,\sqrt {{{10} \over {28}}} = {3 \over 5}} \right)$$
C
Oxygen $$\left( {M = 32,\sqrt {{{10} \over {32}}} = {9 \over {16}}} \right)$$
D
Argon $$\left( {M = 36,\sqrt {{{10} \over {36}}} = {{17} \over {32}}} \right)$$
4
JEE Advanced 2013 Paper 2 Offline
MCQ (More than One Correct Answer)
+4
-2

Two vehicles, each moving with speed u on the same horizontal straight road, are approaching each other. Wind blows along the road with velocity w. One of these vehicles blows a whistle of frequency f1. An observer in the other vehicle hears the frequency of the whistle to be f2. The speed of sound in still air is V. The correct statement(s) is(are)

A
If the wind blows from the observer to the source, f2 > f1.
B
If the wind blows from the source to the observer, f2 > f1.
C
If the wind blows from the observer to the source, f2 < f1
D
If the wind blows from the source to the observer, f2 < f1.
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