MCQ
An echo is heard when the minimum distance of the reflecting surface is:
- A10 cm
- B340 m
- C34 m
- D17 m
✓
Answer
D. 17 m
Explanation:
The minimum distance for echo hearing is,
$\Delta x=\frac{1}{2}(v \times \Delta t)$
velocity of sound $v =340 m / sec$, minimum time to return sound $t =0.1 sec$ so required distance $=\frac{1}{2}\left(340 \times \frac{1}{10}\right)=17 m$
Explanation:
The minimum distance for echo hearing is,
$\Delta x=\frac{1}{2}(v \times \Delta t)$
velocity of sound $v =340 m / sec$, minimum time to return sound $t =0.1 sec$ so required distance $=\frac{1}{2}\left(340 \times \frac{1}{10}\right)=17 m$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Energy in a current carrying coil is stored in the form of
The de-Broglie wavelength of an electron having $80eV$ of energy is nearly .............. $\mathop {\rm{A}}\limits^o $ ($1eV = 1.6 ×10^{-19} J$, Mass of electron $= 9 ×10^{-31} kg$ Plank’s constant $= 6.6 × 10^{-34}$ $J-sec$)
→Two parallel large thin metal sheets have equal surface charge densities $(\sigma = 26.4 \times 10^{-12}\,c/m^2)$ of opposite signs. The electric field between these sheets is
→If a thin mica sheet of thickness $'t'$ and refractive index $\mu = 5/3$ is placed in the path of one of the interfering beams as shown in fig. then the displacement of the fringe system is
→Which of the following is not a perfectly inelastic collision
The voltage drop across $15\, \Omega$ resistance in the given figure will be $.....V.$
→The tiny ball at the end of the thread shown in figure has a mass of $0.5 \, g$ and is placed in a horizontal electric field of intensity $500\, N/C$. It is in equilibrium in the position shown. The magnitude and sign of the charge on the ball is .....$\mu C$
→Consider a plane parallel beam of light incident on a plano-cylindrical lens as shown below. Which of the following will you observe on a screen placed at the focal plane of the lens?
$C{O_2}(O - C - O)$ is a triatomic gas. Mean kinetic energy of one gram gas will be (If $N-$Avogadro's number, $k-$Boltzmann's constant and molecular weight of $C{O_2} = 44$)
→The output of an $OR$ gate is connected to both the inputs of a $NAND$ gate. The combination will serve as a
→