CHAP#8  WAVES.

385. The mechanism by energy is transferred from one point to another point is  Wave motion

386. Waves which required medium like sound and water waves are called Mechanical waves

387. Waves which required no medium like heat, light and radio waves are called Electromagnetic waves

388. Particles of waves vibrate perpendicular to the direction of the propagation of waves in Transverse waves

389. Particles of waves vibrate parallel to the direction of the propagation of waves in Longitudinal waves

390. In transverse waves the particle vibrate with the period and frequency of the  Source

391. Mechanical waves cannot propagate through Gases

392. The time for one vibration is called Time period

393. In nature sound waves are Compressional

394.   √                                          √          Speed of transverse wave

395.   √     Speed of longitudinal waves

396. Speed of sound founded by Newton 281 m s-1

397. Speed of sound of Laplace’s correction 332 m s-1

398. Theoretical value of sound is 16% less than  Experimental value

399. Propagation of sound waves through air or gas is an Adiabatic process

 400. Increase in speed of sound for each degree rise above 00 C is 0.61 m s-1

401. Speed of sound is directly proportional to the Moisture and  temperature

 402. Speed of sound is inversely proportional to the Density

403. Speed of sound is independent to the Pressure

404. The effect produced by the superposition of waves from two coherent sources, passing through same region is called Interference

405. In case of transverse waves constructive interference will occur if crest of one waves meet with another Crest of another wave

406. In case of longitudinal waves constructive interference will occur if compression of one waves meet with another Compression of another wave

 407. If two waves arrive at same place at the same time but are out of phase(1800) Destructive interference occur

408. The difference between frequencies of two waves is called Beat frequency(N)

 409. N =f = 1/T

410. The phenomenon of beats is used in finding unknown Frequencies

 411. Perceived fundamental frequency of sound is Pitch

 412. In reflection of mechanical waves the angle between incident and reflected pulse is λ/2 or π or 1800

413. When transverse wave on string is reflected from a denser medium, there is a  phase change of 1800

414. When transverse wave on string is reflected from a rare medium, it suffers  No phase change

415. The reflection of original sound from a certain object is received at 0.1 sec later than the direct sound is called Echo

416. The effective distance for echo is 17m

417. Stationary waves is also called Standing waves

418. The distance between two successive nodes or anti-nodes is equal to the  λ/2

 419. The lowest characteristics frequency of vibration f1 is called 1st harmonic or Fundamental frequency

420. When source moves towards stationary listener, then the  frequency of sound Increases

421. When source of sound moves away from stationary listener, then frequency Decreases

 422. When the listener moves towards stationary source, then frequency of sound Increases

423. When the listener moves away from source, then the  frequency of sound Decreases

424. When source and listener both moves towards each other, then the frequency  Increases

425. When source and listener moves away from each other, then the frequency Decreases

426. Doppler effect is not confined to  Sound waves

427. Doppler effect is applicable for Light waves

 428. When ultrasonic waves are focused on a small space in liquid , the liquid is rapidly volatilized and large number of bubbles are formed this process is called Cavitaions 

429. The transverse nature of light is verified with the phenomenon of  polarization

430. The phase changes of 1800 is equivalent to λ/2

431. When water reach to an obstacle in the medium, they bend around the region behind it, this is the evidence of the phenomenon of Diffraction

432. Electromagnetic waves do not require medium for their Propagation

 433. When longitudinal waves propagate through a medium , the particle of the medium Vibrate parallel to the direction of wave

 434. The wavelength of sound made from a tuning fork of frequency 330 Hz is nearly 330m (v=f λ)

 435. Two waves of same frequency and amplitude traveling in opposite direction along same position the waves is Stationary waves

436. If tension in a string remains constant and diameter becomes double its speed   Will become half

437. In transverse waves the distance between consecutive crust and trough is  λ/2

 438. To find speed of wave we use V in obstacle = f λ

439. Constructive interference occur if path difference between two monochromatic light is Integral multiple of wavelength

440. γ- rays have high energy photons than x-rays, Ultra violet and  Visible light

441. The radio waves of constant magnitude are called Carrier waves

 442. The world seismology stands for An instrument used for detecting earthquakes

 443. The motion of the source of sound with respect to stationary listener cause change in Frequency of sound

444. One light year is equal to 9.46 x 1015 m

445. Sound waves move faster in Hydrogen medium

446. The velocity of earth satellite can be measured from the change in frequency or radio waves by using  Doppler effect

447. Frequency of light does not change with  Nature of medium

448. The phase change of 1800 is equal to path difference  Half the wavelength

 449. If the width on the young’s double slit experiment becomes double, the fringe spacing will become  Half

 450. Doppler effect is applicable to Sound and light waves