NCERT Solutions
Board Paper Solutions
Ask & Answer
School Talk
Login
GET APP
Login
Create Account
Popular
Latest
Expert Answers
ALL
Rijo
Subject: Physics
, asked on 4/3/18
The physics teacher, while teaching the topic ‘organ pipes’, explained to her students the
reason, for the change in the fundamental frequency (and the frequencies of harmonics),
when one end of an open organ pipe is closed. She went on say that we can expect a
similar ‘change pattern’ when we tend to give up an ‘open approach’ to our learning.
She advised her students to ‘keep open’ all avenues of learning so that their learning can
be built upon all aspects of their fundamental training. She also advised them to work hard in a dedicated way so that their extra effort pushes up their ‘learning Wavelengths’
in much the same way. As an increase in the length of an organ pipe does to 1st
fundamental wavelength. State what in your opinion, are the two values conveyed by
the teacher, to her students through her lecture. Also state the value of the ‘fundamental
mode wavelength’ associated with (i) an open organ pipe of length L, (ii) a closed
organ pipe of length L.
State how the wavelengths of the permitted normal modes, of the above two types of
organ pipes, are related to their fundamental wavelengths
Answer
1
Rijo
Subject: Physics
, asked on 4/3/18
The physics teacher, while teaching the topic ‘organ pipes’, explained to her students the
reason, for the change in the fundamental frequency (and the frequencies of harmonics),
when one end of an open organ pipe is closed. She went on say that we can expect a
similar ‘change pattern’ when we tend to give up an ‘open approach’ to our learning.
She advised her students to ‘keep open’ all avenues of learning so that their learning can
be built upon all aspects of their fundamental training. She also advised them to work hard in a dedicated way so that their extra effort pushes up their ‘learning Wavelengths’
in much the same way. As an increase in the length of an organ pipe does to 1st
fundamental wavelength. State what in your opinion, are the two values conveyed by
the teacher, to her students through her lecture. Also state the value of the ‘fundamental
mode wavelength’ associated with (i) an open organ pipe of length L, (ii) a closed
organ pipe of length L.
State how the wavelengths of the permitted normal modes, of the above two types of
organ pipes, are related to their fundamental wavelengths
Answer
1
Ian Colaco
Subject: Physics
, asked on 27/2/18
derive an expression for the apparent frequency of a sound wave when the listener moves towards the stationary source using Doppler effect in sound.
Answer
2
Malika Sood
Subject: Physics
, asked on 25/2/18
When stationary wave is produced certain particles of the medium always remain at their positions and certain other positions particles vibrate simple harmonically about the mean positions with double the amplitude of each wave.
Answer
1
Kunal Singh
Subject: Physics
, asked on 24/2/18
answer q 10 asap
Q.10. Two tuning forks A and B, when sounded together they produce 20 beats in 4 sec. On filing a tuning fork A, the no. of beats become 6 beats/ sec. Calculate the frequency of B if the frequency of A is 512 Hz.
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
Two superimposing waves are represented by equation
y
1
= 2 sin 2π (10
t
– 0.4
x
) and
y
2
= 4 sin 2π (20
t
– 0.8
x
). The ratio of
I
max
to
I
min
is
(1) 36 : 4 (2) 25 : 9 (3) 1 : 4 (4) 4 : 1
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
Solve this:
Q.4. Two waves of frequency 500 Hz and 498 Hz are produced simultaneously. Calculate the time interval between successive maxima.
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
Solve this:
Q.9. An iron block is dropped into a deep well. Sound of splash is heard after 4.23 s. If the depth of the well is 78.4 m, then find the speed of sound in air (g = 9.8
m
/
s
2
)
(1) 300 m/s
(2) 320 m/s
(3) 280 m/s
(4) 340.8 m/s
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
Solve this:
Q.10. If the intensity of sound is increased by a factor of 30, by how many decibels is the sound level increase?
(1) 12 dB
(2) 14.77 dB
(3) 10 dB
(4) 13 dB
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
7
.
A
c
o
p
p
e
r
w
i
r
e
i
s
h
e
l
d
a
t
t
h
e
t
w
o
e
n
d
s
b
y
r
i
g
i
d
s
u
p
p
o
r
t
s
.
A
t
50
°
C
t
h
e
w
i
r
e
i
s
j
u
s
t
t
a
u
t
,
w
i
t
h
n
e
g
l
i
g
i
b
l
e
t
e
n
s
i
o
n
,
i
f
Y
=
1
.
2
×
10
11
N
/
m
2
,
α
=
1
.
6
×
10
-
5
/
°
C
a
n
d
ρ
=
9
.
2
×
10
3
K
g
/
m
3
,
t
h
e
n
t
h
e
s
p
e
e
d
o
f
t
r
a
n
s
v
e
r
s
e
w
a
v
e
s
i
n
t
h
i
s
w
i
r
e
a
t
30
°
C
i
s
1
64
.
6
m
/
s
2
16
.
2
m
/
s
3
23
.
2
m
/
s
4
32
.
2
m
/
s
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
Solve this:
Q.6. The speed of sound in hydrogen at NTP, is 1270 m/s. Then the speed in a mixture of hydrogen and oxygen in the ratio 4 : 1 by volume, (in m/s) will be
(1) 635
(2) 318
(3) 158
(4) 1270
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 23/2/18
Give reasons as well.for both the cases
Q). What kind of mechanical waves exist
(a) Inside water?
(b) On the surface of water?
Answer
1
Shreya Choudhary
Subject: Physics
, asked on 21/2/18
Solve this:
Q. A string of length 4 m and mass 160 g is fixed at one end and its other end is tied with a light string having the same length. Calculate the wavelengths and frequencies of the fundamental and first two overtones if the tension in the spring is 400 N.
Answer
1
Tulsi Mehta
Subject: Physics
, asked on 18/2/18
Do the following points represent nodes ?
Answer
1
Tulsi Mehta
Subject: Physics
, asked on 18/2/18
Why is 12 pi added at last ?
Q. Example 15.2
A wave travelling along a string is describe by,
y (x ,t) = 0.005 sin (80.0 x – 3.0 t),
in which the numerical constants are in SI units (0.005 m, 80.0 and m
–1
, and 3.0 rad S
–1
), Calculate (a) the amplitude. (b) the wavelength, and (c) the period and frequency of the wave. Also, calculate the displacement y of the wave at a distance
x
= 30.0 cm and time
t
= 20 s ?
The displacement y at x = 30.0 cm and time t = 20 s is given by
y = (0.005 m ) sin ( 80.0 × 0.3 – 3.0 × 20)
= (0.005 m) sin ( – 36 + 12
π
)
= (0.00 5 m) sin (1.699)
= (0.005 m ) sin ( 97
0
)
≃
5 mm
Answer
1
Prev
1
2
3
4
5
Next
What are you looking for?
reason, for the change in the fundamental frequency (and the frequencies of harmonics),
when one end of an open organ pipe is closed. She went on say that we can expect a
similar ‘change pattern’ when we tend to give up an ‘open approach’ to our learning.
She advised her students to ‘keep open’ all avenues of learning so that their learning can
be built upon all aspects of their fundamental training. She also advised them to work hard in a dedicated way so that their extra effort pushes up their ‘learning Wavelengths’
in much the same way. As an increase in the length of an organ pipe does to 1st
fundamental wavelength. State what in your opinion, are the two values conveyed by
the teacher, to her students through her lecture. Also state the value of the ‘fundamental
mode wavelength’ associated with (i) an open organ pipe of length L, (ii) a closed
organ pipe of length L.
State how the wavelengths of the permitted normal modes, of the above two types of
organ pipes, are related to their fundamental wavelengths
reason, for the change in the fundamental frequency (and the frequencies of harmonics),
when one end of an open organ pipe is closed. She went on say that we can expect a
similar ‘change pattern’ when we tend to give up an ‘open approach’ to our learning.
She advised her students to ‘keep open’ all avenues of learning so that their learning can
be built upon all aspects of their fundamental training. She also advised them to work hard in a dedicated way so that their extra effort pushes up their ‘learning Wavelengths’
in much the same way. As an increase in the length of an organ pipe does to 1st
fundamental wavelength. State what in your opinion, are the two values conveyed by
the teacher, to her students through her lecture. Also state the value of the ‘fundamental
mode wavelength’ associated with (i) an open organ pipe of length L, (ii) a closed
organ pipe of length L.
State how the wavelengths of the permitted normal modes, of the above two types of
organ pipes, are related to their fundamental wavelengths
Q.10. Two tuning forks A and B, when sounded together they produce 20 beats in 4 sec. On filing a tuning fork A, the no. of beats become 6 beats/ sec. Calculate the frequency of B if the frequency of A is 512 Hz.
(1) 36 : 4 (2) 25 : 9 (3) 1 : 4 (4) 4 : 1
Q.4. Two waves of frequency 500 Hz and 498 Hz are produced simultaneously. Calculate the time interval between successive maxima.
Q.9. An iron block is dropped into a deep well. Sound of splash is heard after 4.23 s. If the depth of the well is 78.4 m, then find the speed of sound in air (g = 9.8 )
(1) 300 m/s
(2) 320 m/s
(3) 280 m/s
(4) 340.8 m/s
Q.10. If the intensity of sound is increased by a factor of 30, by how many decibels is the sound level increase?
(1) 12 dB
(2) 14.77 dB
(3) 10 dB
(4) 13 dB
Q.6. The speed of sound in hydrogen at NTP, is 1270 m/s. Then the speed in a mixture of hydrogen and oxygen in the ratio 4 : 1 by volume, (in m/s) will be
(1) 635
(2) 318
(3) 158
(4) 1270
Q). What kind of mechanical waves exist
(a) Inside water?
(b) On the surface of water?
Q. A string of length 4 m and mass 160 g is fixed at one end and its other end is tied with a light string having the same length. Calculate the wavelengths and frequencies of the fundamental and first two overtones if the tension in the spring is 400 N.
Q. Example 15.2 A wave travelling along a string is describe by,
y (x ,t) = 0.005 sin (80.0 x – 3.0 t),
in which the numerical constants are in SI units (0.005 m, 80.0 and m–1, and 3.0 rad S–1), Calculate (a) the amplitude. (b) the wavelength, and (c) the period and frequency of the wave. Also, calculate the displacement y of the wave at a distance x = 30.0 cm and time t = 20 s ?
The displacement y at x = 30.0 cm and time t = 20 s is given by
y = (0.005 m ) sin ( 80.0 × 0.3 – 3.0 × 20)
= (0.005 m) sin ( – 36 + 12 )
= (0.00 5 m) sin (1.699)
= (0.005 m ) sin ( 970 ) 5 mm