11- Chapter Numericals || 10th class physics || sound problems || matric physics
This video is related to 11 chapter (Sound) numericals of 10th class physics.(Punjab textbook) @fanticer
0:06. A normal conversation involves sound
intensities of about 3.0×10-⁶ Wm–². What
is the decibel level 🎚️ for this intensity?
What is the intensity of the sound for
100 dB ?
( 64.8 dB, 0.01 Wm–² )
8:17. If at Anarkali Bazar Lahore, intensity level
of sound is 80 dB, what will be the
intensity of sound there ?
( 10–⁴ Wm–² )
11:24. At a particular temperature🌡️, the speed
sound in air is 330ms-¹. If the wavelength
of a note 🎵 is 5cm, calculate the
frequency of the sound wave. Is this
frequency in the audible range of the
human ear?
( 6.6×10³ Hz )
14:47. A doctor counts 72 heartbeats in 1 min.
Calculate the frequency and period of the
heartbeats.
(1.2 Hz, 0.83 s)
16:44. A marine survey ship 🚢 sends a sound
wave staright to the seabed. It receives
an echo 1.5 s later. The speed of sound
in seawater is 1500 ms-¹. Find the depth
of the sea at this position.
( 1125 m )
21:05. A student clapped his hands near a cliff
and heard the echo after 5s. What is the
distance of the cliff from the student if
the speed of the sound is taken as
346 ms-¹?
( 865 m )
23:47. A ship sends out ultrasound that returns
from the seabed and is detected after
3.42 s. If the speed of ultrasound
through seawater is 1531 ms-¹, what is
the seabed from the ship?
( 2618 m )
26:14. The highest frequency sound humans
can hear is about 20,000Hz. What is the
wavelength of sound in air at this
frequency at a temperature of 20°C?
What is the wavelength of the lowest
sounds we can hear of about 20 Hz ?
Assume the speed of sound in air at
20°C? Assume the speed of sound in air
at 20°C is 343 ms-¹.
( 1.7 × 10-²m, 17.2 m )
30:30. A sound wave has a frequency of 2kHz
and wavelength 35 cm. How long will it
take to travel 1.5 km ?
(2.1s)