Question
What should be the minimum distance between source and reflector in water so that echo is heard distinctly?
(The speed of sound in water $= 1400 m s^{-1})$
(The speed of sound in water $= 1400 m s^{-1})$
✓
Answer
Velocity = 2D/Time
$1400 = 2 \times D/ 0.1$
$D = 1400 \times 0.1/ 2 = 70 m$
$1400 = 2 \times D/ 0.1$
$D = 1400 \times 0.1/ 2 = 70 m$
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
How is the working of an electric bell affected, if alternating current be used instead of direct current?
Give scientific reasons for the following:
A steam burn is usually worse than a hot water burn.
A steam burn is usually worse than a hot water burn.
In the diagram below, PQ is a ray of light incident on a rectangular glass block.
How are the angles ‘i’ and ‘e’ related to each other?
How are the angles ‘i’ and ‘e’ related to each other?
(i) A straight wire conductor passes vertically through a piece of cardboard sprinkled with iron filings. Copy the diagram and show the setting of iron filings when a current is passed through the wire in the upward direction and the cardboard is tapped gently. Draw arrows to represent the direction of the magnetic field lines.
(ii) Name the law which helped you to find the direction of the magnetic field lines.
(ii) Name the law which helped you to find the direction of the magnetic field lines.
It is much easier to skate on rough ice than on glass. Give reasons.
What distinguish is the sound from two musical instruments even if they are of the same pitch and same loudness?
A boy pulls a box up to $10\ m$ with a force of $5\ kgf$. Calculate the work done by him.
→A charge of 80 C flows in a conductor for 2 minutes.
(a) Calculate the current flowing through the conductor.
(b) If the current through a heater is 4 A what charge must be passing in 8 seconds?
(a) Calculate the current flowing through the conductor.
(b) If the current through a heater is 4 A what charge must be passing in 8 seconds?
Mention one difference between reflection of light from a plane mirror and total internal reflection of light from a prism.
What do you understand by a simple machine?