Beat Frequency

Q. The fundamental frequency of a string stretched with a block of mass 4 kg is 256 hz. The mass of block required to produce its octave is

Q.

Two tuning forks when sounded together produced 4 beats/sec. The frequency of one fork is 256. The number of beats heard increases when the fork of frequency 256 is loaded with wax. The frequency of the other fork is

[CPMT 1976; MP PMT 1993]

1. 520

2. 260

3. 504

4. 252

Q.

Two tuning forks A and B vibrating simultaneously produce 5 beats. Frequency of B is 512. It is seen that if one arm of A is filed, then the number of beats increases. Frequency of A will be

1. 502

2. 507

3. 517

4. 522

Q.

In a sonometer experiment, the string of length $‘L’$ under tension vibrates in a second overtone between two bridges. Where is the amplitude of vibration maximum at?

Q.

If the velocity of sound in air is 350 m/s. Then the fundamental frequency of

an open organ pipe of length 50 cm, will be

1. 350 Hz

2. 175 Hz

3. 900 Hz

4. 750 Hz

Q.

A tuning fork of frequency 100 when sounded together with another tuning fork of unknown frequency produces 2 beats per second. On loading the tuning fork whose frequency is not known and sounded together with a tuning fork of frequency 100 produces one beat, then the frequency of the other tuning fork is

[NCERT 1977]

1. 102

2. 98

3. 99

4. 101

Q. A 12 m long vibrating string has the speed of wave 48 m/s To what frequency it will resonate

Q.

A resonance air column of length 20 cm resonates with a tuning fork of frequency

250 Hz. The speed of sound in air is

[AFMC 1999; BHU 2000; CPMT 2001]

1. 300 m/s

2. 200 m/s

3. 150 m/s

4. 75 m/s

Q. Two sitar strings A and B playing the note ‘Ga’ are slightly out of tune and producebeats of frequency 6 Hz. The tension in the string A is slightly reduced and thebeat frequency is found to reduce to 3 Hz. If the original frequency of A is 324 Hz, what is the frequency of B?

Q.

If the displacement of a particle executing SHM is given by y = 0.30 sin ( 220t + 0.64 ) in metre, then the frequency and maximum velocity of the particle is

[AFMC 1998]

1. 58 Hz, 113 m / s

2. 35 Hz, 66 m / s

3. 45 Hz, 66 m / s

4. 35 Hz, 132 m / s

Q.

A pipe of length $85cm$ is closed from one end. Find the number of possible natural oscillations of the air column in the pipe whose frequencies lie below $1250Hz$. The velocity of sound in the air is $340\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right..$

1. $6$

2. $4$

3. $12$

4. $8$

Q. A tuning fork $A$ when sounded with a tuning fork $B$ of frequency $480\text{Hz}$ produces $5$ beats per second. When the prongs of $A$ are loaded with wax, it gives $3$ beats per second. The original frequency of the tuning fork $A$ is:

1. $475\text{Hz}$
2. $485\text{Hz}$
3. $483\text{Hz}$
4. $477\text{Hz}$

Q. 5.An open organ pipe has a fundamental frequency 300 hertz. The frequency of first overtone of this pipe is the same as the first overtone of the closed organ pipe, the length of the closed organ pipe is? (Velocity of the sound is equals to 330 metre per second) 1)41 cm 2) 75 cm 3)390 cm 4)482 cm

Q. Three sound waves of equal amplitudes have frequencies $(n–1),n,(n+1)$. They superimpose to give beats. The number of beats produced per second will be

1. 3
2. 2
3. 1
4. 4

Q. A 1.00*10-20 kg particle is vibrating under simple harmonic motion with a period of 1*10-5 s and with a maximum speed of 1*103 m/s.The maximum displacement of the particle from mean position

Q.

For the stationary wave y = 4 sin $\left(\frac{\pi x}{15}\right)cos\left(96\pi t\right)$ , the distance between

anodeand the next antinode is

[MP PMT 1987]

1. 15

2. 7.5

3. 22.5

4. 30

Q. 6. A tuning fork and an air column whose temperature is 51�C produce 4 beats in one second, when sounded together. When the temperature of air column decrease the number of beats per second decrease. When the temperature remains 16�C only one beat per second is produced. The frequency of the tuning fork is 1) 100HZ 2) 75 Hz 3) 150Hz 4) 50Hz

Q. If two tuning forks A and B are sounded together, the number of beats produced per second is 5. The frequency of A is 250Hz. If the load is attached to tuning fork B, again sounded together, the number of beats produced per second is 3. The frequency of B is

Q. In a certain oscillatory system, the amplitude ofmotion is 5 m and the time period is 4 s. The timetaken by the particle for passing between pointswhich are at distances of 4 m and 2 m from thecentre and on the same side of it will be(d) 0.35 s(a) 0.30 s (b) 0.32 s (c) 0.33 s

Q. A tuning fork vibrating with a sonometer in fundamental mode having a wire of length $20\text{cm}$ produces $5$ beats per second. The beat frequency does not change if the length of the wire is changed to $21\text{cm}$. The frequency of the tuning fork is

1. $200\text{Hz}$
2. $210\text{Hz}$
3. $205\text{Hz}$
4. $215\text{Hz}$

Q. In a resonance tube experiment, tuning fork A is in resonance with air column of length $40\text{cm}$ and tuning fork B is in resonance with air column of length $41\text{cm}$.
Two tuning forks A and B sounded together produce $10$ beats per second. Calculate the frequencies of forks.
(Assume fundamental mode for air column)

1. $400\text{Hz},390\text{Hz}$
2. $430\text{Hz},410\text{Hz}$
3. $410\text{Hz},400\text{Hz}$
4. $410\text{Hz},420\text{Hz}$

Q. Two sources A and B are sounding notes of frequency 680 Hz. A listener moves from A to B with a constant velocity u. If the speed of sound is 340 m/s, what must be the value of u so that he hears
10 beats per second?

1. 2.0 m/s
2. 2.5 m/s
3. 30 m/s
4. 3.5 m/s

Q. Two strings (fixed at both ends) $P$ and $Q$ of equal length, made of same material and vibrating in same mode produces beats of frequency $5\text{Hz}$. String $Q$ is vibrating at a frequency $460\text{Hz}$. If the tension in string $P$ increases, the beat frequency increases to $7\text{Hz}$. The initial frequency of vibration for string $P$ is :

1. $455\text{Hz}$
2. $465\text{Hz}$
3. $453\text{Hz}$
4. $462\text{Hz}$

Q. Q, .Displacement x of a simple harmonic oscillator varies with time, according to differntial euation d^2x/dt^2 +4x =0 Then its time period will be?

Q. The frequency of tuning forks A and B are respectively 3% more and 2% less than the frequency of tuning fork C.When A and B are simul†an eously excited , 5 beats per second are produced.Then the frequency of the tuning fork A in Hz is?

Q. A thin fork and an air column whose temperature is 51^0C produce 4 beats per second, when sounded together. When the temperature of air column decreases the no. Of beats per second decreases. When the temperature remains 16^0C only one beat per second is produced. The frequency of the tuning fork is A)100Hz B)75Hz C)150Hz D)50Hz

Q.

When a tuning fork of frequency 341 is sounded with another tuning fork, six

beats per second are heard. When the second tuning fork is loaded with wax

and sounded with the first tuning fork, the number of beats is two per

second. The natural frequency of the second tuning fork is

[MP PET 1989]

1. 334

2. 339

3. 343

4. 347

Q. a tuning fork produces 4 beats per second in a column of air at 57 degree celcius. when temperature is decreased by 9 degree celsius the two produces 1 beat per secoond . the frequency of tuning fork is 103 hz 213 hz 120 hz 37 hz

Q. ntA band playing music at a frequency f is moving towards a wall at a speed Vb.A motorist is following the band with a speed Vm.If V be the speed of the sound, the expression beat frequency heard by motorist isn

Q. a band playing music at frequency f is moving towards a wall with speed vb. A MOTORIST is following the band with speed vm. if v is speed of sound then the expression of beat frequency heard by motorist is