AIIMS Physics Waves Class 11 Questions

A string wave equation is given y = 0.002sin(300t - 15x) and mass density is μ = 0.1 kg/m. Then find the tension in the string.

A string wave equation is given y = 0.002 sin (300t - 15x) and mass density is (μ = 0.1kg/m). Then find the tension in the string.

If speed of sound in air in 330 m/s then, find the number of tones present in an open organ pipe of length 1 m whose frequency if ≤ 1000.

An observer hears 3 beats/s when two sources A and B are sounded together. If the frequency of source A is 256 Hz, what is the speed of source B?

The harmonic equations are given as, x₁ = 5sin(2πt + π/4) x₂ = 5√2(sin πt + cos 2πt) The amplitude are, A₁ = 5 A₂ = √((5√2)² + (5√2)²) = 10 The ratio of the amplitude is, A₁/A₂ = 5/10 = 1:5

First resonance, l₁ + x = λ/4 = 22.7 ……(I) Second resonance, l₂ + x = 3λ/4 = 70.2 ……(II) Third resonance, l₃ + x = 5λ/4 ……(III) From equations (I) and (II),

FM broadcast is better than AM broadcast because noise change is maximum in amplitude of AM waves. FM broadcast is better than AM broadcast because in AM broadcast electric signals superimpose with main signal.

In ionospheric reflection, phase change does not occurs with the light wave because the ionosphere reflection is similar to the total internal reflection is similar to the total internal reflection in miraj and in total internal reflection the reflection occurs from a rarer medium, so the reflected ray does not get inverted in phase.

Assertion: The change in air pressure effect the speed of sound. Reason: The speed of sound in a gas is proportional to the square of pressure.

In a modulated signal the maximum amplitude is 15 Volt and minimum amplitude is 5 Volt, the amplitude of signal wave will be:

The pair of forks produces 4 beats/sec. So, the frequency of both forks differs by 4. The possible frequency of unknown fork is 284 cps or 292 cps. According to the second condition, the difference in their frequencies are 2. It is only possible when the unknown fork has a higher frequency than the given fork frequency i.e., 292 cps.

Vibrations are produced in a vertical tube of length 150 cm closed at one end by a tuning fork of frequency 340 Hz. Now water is filled slowly in the tube. If the speed of sound in air is 340 m/s then the minimum height of water required for resonance is

Three waves of equal frequency having amplitudes 10 mm, 4mm and 7 mm arrive at a given point with successive phase difference of π/2. The amplitude of the resulting wave in mm is given by:

After 2 s, each wave travels a distance = 2 × 2 = 4 m. The wave shape is shown in figure. Thus, the energy is purely kinetic.

A source producing sound of frequency 170 Hz is approaching a stationary observer with a velocity of 17 m/s. The apparent change in the wavelength of sound heard by the observer is (speed of sound in air = 340 m/s)

On the same path, the source and observer are moving such a ways that the distance between these two increases with the time. The speeds of source and observer are same and equal to 10 ms⁻¹ with respect to the ground while no wind is blowing. The apparent frequency received by observer is 1950 Hz, then the original frequency must be (the speed of sound in present medium is 340 m/s)

\(f_c = 9\sqrt{N_m} = 9\sqrt{9 \times 10^{10}} = 2.7 \text{ MHz}\)

A string wave traveling towards a free end changes its direction of motion but phase remains constant after reflection is a true assertion and when string wave reaches the free end there is no medium present in front of it is a true reason.

Water waves in a river are not polarized because they are longitudinal in nature.

In a string wave, during reflection from fix boundary, the reflected wave is inverted as; the force on string by clamp is in downward direction while string is pulling the clamp in upward direction.

Assertion: Solids can support both longitudinal and transverse waves but only longitudinal waves can propagate in gases. Reason: For the propagation of transverse waves, medium must also necessarily have the property of rigidity.

A wave is represented by the equation \( y = 0.5 \sin(10t - x) \) metre. It is a travelling wave propagating along +x direction with velocity

If the intensity is increased by a factor of 20, then how many decibels in the sound level increased?

On the same path, the source and observer are moving such ways that the distance between these two increases with the time. The speeds of source and observer are same and equal to 10 ms⁻¹ with respect to the ground while no wind is blowing. The apparent frequency received by observer is 1950 Hz, then the original frequency must be (the speed of sound in present medium is 340 m/s)

Assertion In a stationary wave, there is not transfer of energy. Reason There is no outward motion of the disturbance from one particle to adjoining particle in a stationary wave.

For satellite communication which wave is used?

If modulation index is 1/2 and power of carrier wave is 2 W. Then what will be the total power in modulated wave?

Astronomical wavelength increase due to doppler effect known as

Long distance communication between two point on earth is achieved by

What is your observation when two sources are emitting sound with frequency 499 Hz and 501 Hz?

If man were standing unsymmetrically between parallel cliffs, claps his hands and starts hearing a series of echoes at intervals of 1 s. If speed of sound in air is 340 m s⁻¹, the distance between two cliffs would be

When a sound wave goes from air to water, which of the following remains constant?

Assertion : In the transmission of long distance radio signals, short wave band is used. Reason : In shorter wavelength, attenuation is very less.

Assertion : There is a physical significance of matter waves. Reason : Both interference and diffraction occurs in it.

A uniform string is vibrating with a fundamental frequency f. The new frequency if radius & length both are doubled would be

Five sinusoidal waves have the same frequency 500 Hz but their amplitudes are in the ratio 2:1:1:1:1 and their phase angles 0, π, π/3, π/6, π/2 respectively. The phase angle of resultant wave obtained by the superposition of these five waves is

The second overtone of an open pipe has the same frequency as the first overtone of a closed pipe 2 m long. The length of the open pipe is

Two closed organ pipes of length 100 cm and 101 cm produces 16 beats in 20 sec. When each pipe is sounded in its fundamental mode calculate the velocity of sound.

Assertion : In the relation f = \( \frac{1}{2\pi} \sqrt{\frac{T}{\mu}} \), where symbols have standard meaning, \( \mu \) represent linear mass density. Reason : The frequency has the dimensions of inverse of time.

A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s. The frequency of sound heard by listener is (velocity of sound = 300 m/s)

Assertion : Sound waves cannot travel in vacuum but light waves can travel in vacuum. Reason : Sound waves are longitudinal waves and they cannot be polarised but electromagnetic waves are transverse and they can be polarised.

A boat at anchor is rocked by waves whose crests are 100 m apart and velocity is 25 m/sec. The boat bounces up once in every

A stone thrown into still water, creates a circular wave pattern moving radially outwards. If r is the distance measured from the centre of the pattern, the amplitude of the wave varies as

When a guitar string is sounded with a 440 Hz tuning fork, a beat frequency of 5 Hz is heard. If the experiment is repeated with a tuning fork of 437 Hz, the beat frequency is 8 Hz. The string frequency (Hz) is

For a wave propagating in a medium, identify the property that is independent of the others.

The waves produced by a motorboat sailing in water are

An organ pipe closed at one end has fundamental frequency of 1500 Hz. The maximum number of overtones generated by this pipe which a normal person can hear is

An earthquake generates both transverse (S) and longitudinal (P) sound waves in the earth. The speed of S waves is about 4.5 km/s and that of P waves is about 8.0 km/s. A seismograph records P and S waves from an earthquake. The first P wave arrives 4.0 min before the first S wave. The epicenter of the earthquake is located at a distance about

The maximum distance upto which TV transmission from a TV tower of height h can be received is proportional to

In short wave communication, waves of which of the following frequencies will be reflected back by the ionospheric layer having electron density 10¹¹ per m³?