MCQ
The minimum audible wavelength at room temperature is about
  • A
    $0.2 Å$
  • B
    $5 Å$
  • C
    $5\, cm$ to $2\, metre$
  • $20 \,mm$

Answer

Correct option: D.
$20 \,mm$
d
(d) Since maximum audible frequency is $20,000 Hz,$

hence ${\lambda _{\min }} = \frac{v}{{{n_{\max }}}} = \frac{{340}}{{20,000}} \approx 20\,mm$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

$X-$ rays are not used for radar purpose because
A photosensitive metallic surface is illuminated alternately with lights of wavelength $3100 \mathring A$ and $6200 \mathring A$. It is observed that maximum speeds of the photoelectrons in two cases are in ratio $2: 1$. The work function of the metal is ( $h c=12400 \,eV\mathring A$ )
A flywheel is making $\frac{3000}{\pi}$ revolutions per minute about its axis. If the  moment of inertia of the flywheel about that axis is $400\, kgm^2$, its rotational kinetic  energy is 
Two bulbs of $(40 \;W, 200\; V)$ and $(100\; W, 200 \;V)$. Then correct relation for their resistance
A series $LCR$ circuit containing a resistance of $120\, ohm$ has angular resonance frequency $4 \times 10^3 rad \, s^{-1}.$ At resonance, the voltage across resistance and inductance are $60\,V$ and $40\,V$ respectively. The values of $L$ and $C$ are respectively
A simple pendulum is released from rest at the horizontally stretched position. When the string makes an angle $\theta$ with the vertical, the angle $\phi$ which the acceleration vector of the bob makes with the string is given by
A conveyor belt is moving at a constant speed of $2\, m s^{-1}$. A box is gently dropped on it. The coefficient of friction between them is $\mu = 0.5.$ The distance that the box will move relative to belt before coming to rest on it, taking $g = 10\, m s^{-2},$ is $..... m$
A force $F$ is given by $F = at + b{t^2}$, where $t$ is time. What are the dimensions of $a$ and $b$
Which of the following statement is incorrect for a spherical body rolling without slipping on a rough horizontal ground at rest?
Field inside a solenoid is