List of top Physics Questions on Waves asked in JEE Main

The width of fringe is 2 mm on the screen in a double slits experiment for the light of wavelength of 400 nm. The width of the fringe for the light of wavelength 600 nm will be:
A guitar string of length 90 cm vibrates with a fundamental frequency of 120 Hz. The length of the string producing a fundamental frequency of 180 Hz will be _______ cm.
If 917 Å be the lowest wavelength of Lyman series then the lowest wavelength of Balmer series will be _____ Å.
A wire of density \(8 × 10^3\) \(kg/m^3\) is stretched between two clamps 0.5 m apart. The extension developed in the wire is \(3.2 × 10^{–4}\) m. If Y = \(8 × 10^{10}\) \(N/m^2\) , the fundamental frequency of vibration in the wire will be ________Hz.
In an experiment with sonometer when a mass of 180 g is attached to the string, it vibrates with fundamental frequency of 30 Hz. When a mass m is attached, the string vibrates with fundamental frequency of 50 Hz. The value of m is ______g.
A single slit of width a is illuminated by a monochromatic light of wavelength 600 nm. The value of 'a' for which first minimum appears at θ=30° on the screen will be :
The fundamental frequency of vibration of a string stretched between two rigid support is 50 Hz. The mass of the string is 18 g and its linear mass density is 20 g/m. The speed of the transverse waves so produced in the string is_______ ms-1.

As per given figure A, B and C are the first, second and third excited energy level of hydrogen atom respectively. If the ratio of the two wavelengths (ie. \(\frac{λ_1}{λ_2}\)) is \(\frac{7}{4n}\) , then the value of n will be____.
 

third excited energy level of hydrogen atom
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R  
Assertion A: The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction.  
Reason R: The wavelengths of waves are different in different media.  
In the light of the above statements, choose the most appropriate answer from the options given below 
The difference between threshold wavelengths for two metal surfaces A and B having work function \(Φ_A\)= 9 eV and \(Φ_B\) = 4.5 eV in nm is:
{Given, hc = 1242 eV nm}
Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R.  
Assertion A : EM waves used for optical communication have longer wavelengths than that of microwave, employed in Radar technology.  
Reason R : Infrared EM waves are more energetic than microwaves, (used in Radar)  
In the light of given statements, choose the correct answer from the options given below:  
A message signal of frequency 3kHz is used to modulate a carrier signal of frequency 1.5 MHz. The bandwidth of the amplitude modulated wave is 
A proton and an α-particle are accelerated from rest by 2V and 4V potentials, respectively. The ratio of their de-Broglie wavelength is
A beam of light consisting of two wavelengths 7000 Å and 5500 Å is used to obtain interference pattern in Young's double slit experiment. The distance between the slits is 2.5 mm and the distance between the plane of slits and the screen is 150 cm. The least distance from the central fringe, where the bright fringes due to both the wavelengths coincide, is n × 10-5 m. The value of n is_____.

A wire of length 30 cm, stretched between rigid supports, has it’s nth and (n + 1)th harmonics at 400 Hz and 450 Hz, respectively. If tension in the string is 2700 N, its linear mass density is _____ kg/m.

A transverse wave is represented by \(y = 2sin(ωt – kx)\) \(cm\). The value of wavelength (in cm) for which the wave velocity becomes equal to the maximum particle velocity, will be
In the wave equation $y=05 \sin \frac{2 \pi}{\lambda}(400 t-x) m$ the velocity of the wave will be :
Match List-I with List-II List-I List-II
Lis IList II
a.Ultraviolet raysi.Study crystal structure
b.Microwavesii.Greenhouse effect
c.Infrared wavesiii.Sterilizing surgical instrument
d.X-raysivRadar system

Choose the correct answer from the options given below :

Let K1 and K2 be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength λ1 and λ2, respectively are incident on a metallic surface. If λ1 = 3λ2 then:

Match List-I with List-II.

                    List - IList - II
A.Television signal i.03 KHz 
B.Radio signalii.20 KHz
C.High Quality Musiciii.02 MHz
D.Human speechiv.06 MHz 

Choose the correct answer from the options given below:

 

A set of 20 tuning forks is arranged in a series of increasing frequencies. If each fork gives 4 beats with respect to the preceding fork and the frequency of the last fork is twice the frequency of the first, then the frequency of last fork is _______ Hz
Two travelling waves of equal amplitudes and equal frequencies move in opposite directions along a string. They interfere to produce a stationary wave whose equation is given by \(y = (10 cos \ \pi x\ sin \frac {2\pi t}{T})\) cm. The amplitude of the particle at \(x = \frac 43\) cm will be _______ cm.
The frequency of echo will be _______ Hz if the train blowing a whistle of frequency 320 Hz is moving with a velocity of 36 km/h towards a hill from which an echo is heard by the train driver. Velocity of sound in air is 330 m/s.
Two cars are approaching each other at an equal speed of 7.2 km/hr. When they see each other, both blow horns having frequency of 676 Hz. The beat frequency heard by each driver will be ______ Hz. [Velocity of sound in air is 340 m/s.]
Two waves are simultaneously passing through a string and their equations are :
\(y_1 = A_1 \sin k(x - vt), y_2 = A_2 \sin k(x-vt+x_0)\). Given amplitudes \(A_1 = 12\) mm and \(A_2 = 5\) mm, \(x_0=3.5\) cm and wave number \(k=6.28\) cm\(^{-1}\). The amplitude of resulting wave will be __________ mm.