MHT CET 2024 3rd May Morning Shift | Waves Question 57 | Physics

The pitch of a whistle of an engine appears to drop by $30 \%$ of original value when it passes a stationary observer. If the speed of sound in air is $350 \mathrm{~ms}^{-1}$, then the speed of engine in $\mathrm{ms}^{-1}$ is

840

700

175

150

MHT CET 2024 3rd May Morning Shift

MCQ (Single Correct Answer)

-0

The displacement of a wave is given by $y=0.002 \sin (100 t+x)$ where ' $x$ 'and ' $y$ ' are in metre and ' $t$ ' is in second. This represents a wave

of wavelength one metre

travelling with a velocity of $100 \mathrm{~m} / \mathrm{s}$ in the negative $x$-direction

of frequency $\left(\frac{100}{\pi}\right) \mathrm{Hz}$

travelling with a velocity of $\left(\frac{50}{\pi}\right) \mathrm{m} / \mathrm{s}$ in the positive x -direction

MHT CET 2024 2nd May Evening Shift

MCQ (Single Correct Answer)

-0

In a vibrating string with fixed ends the waves are of type

stationary longitudinal.

stationary transverse.

progressive transverse.

progressive longitudinal.

MHT CET 2024 2nd May Evening Shift

MCQ (Single Correct Answer)

-0

The driver of a car travelling with a speed ' $V_1$ ' $\mathrm{m} / \mathrm{s}$ towards a wall sounds a siren of frequency ' $n$ ' Hz. If the velocity of sound in air is ' V ' $\mathrm{m} / \mathrm{s}$, then the frequency of the sound reflected from the wall and as heard by the driver in Hz is

$\left(\frac{V_1}{V-V_1}\right) n$

$\left(\frac{V_1-V}{V+V_1}\right) n$

$\left(\frac{V+V_1}{V-V_1}\right) n$

$\left(\frac{V-V_1}{V+V_1}\right) n$

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