Ultrasonic, infrasonic and audio waves travel though a medium with speeds `V_(u), V_(i)` and `V_(a)` respectively then :-

Ultrasonic, Infrasonic and Audible waves travel through a medium with speeds v_(u), v_(l), v_(a) respectively, then

Two trains A and B travel in two parallel rain tracks in opposite direction with speed v_(1) and v _(2) respectively. They take 4 s to pass each other at this speed. If thte speed of train A is increased by 50% then they take 3 s to pass each other. The ratio of v_(1)//v_(2) is

A particle of mass m moving with velocity u_(1) collide elastically with another particle of same mass moving with velocity u_(2) in the same direction. After collision their speeds are v_(1) and v_(2) respectively then (A) u_(1)+v_(1)=v_(2)+u_(2) , (B) u_(1)-v_(1)=v_(2)+u_(2)

If a wave of wavelength lambda is travelling in a medium with velocity V, then its frequency is

A transverse wave y=A sin omega (x/V_(1) -t) is travelling in a medium with speed V_(1) . Plane x = 0 is the boundary of the medium. For x gt 0 there is a different medium in which the wave travels at a different speed V_(2) . Part of the wave is reflected and part is transmitted. For x lt 0 the wave function is described as y_(-)=A_(1) sin omega (x/V_(1)-t)+A_(2) sin omega (x/V_(2)+t) while for x gt 0, y_(+)=A_(3) sin omega(x/V_(2)-t) (a) Using the fact that the wave function must be continuous at x = 0 , show that A_(1) – A_(2) = A_(3) (b) Using the fact that (del y)/(del x) must be continuous at x = 0 , prove that V_(2)/V_(1) A_(1)=A_(3)-A_(2) (c) Show that A_(3)=(2V_(2)A_(1))/(V_(1)+V_(2)) and A_(2)=(V_(1)-V_(2))/(V_(1)+V_(2))A_(1)

Two strings A and B, made of same material, are stretched by same tension. The radius of string A is double of the radius of B. A transverse wave travels on A with speed u_(A) and B with speed v_(B) . The ratio V_(A)// U_(B) is

Ultrasonic and Infrasonic Waves: The sound having frequency 20 Hz to 20 KHz is called audible sound Human ear cannot hear sound of frequencies lying outside this range. The limits of audibility of sound vary from individual. Generally the upper limit decreases with increase of age of individual, usually and people can not hear sound of frequency more than 15 kHz. Sound of frequencies below 20 Hz are called infrasonics, while frequencies beyond 20 kHz are called ultrasonics. Ultrasonics can be heard by dogs, cat bats etc. Bats detect the path by means of ultrasonics. Ultrasonics can be used for diagnosis of tumour and other abnormalities within our body. This is known as ultrasonography. Ultrasonics are used to curve various diseases and to measure depth of oceans to detect submarines. If speed of infrasonics, a audible and ultrasonics waves are v_(i) , v_(a) and v_(u) then A. v_(i) > v_(a) > v_(u) B. v_(i) = v_(a) = v_(u) C. v_(i) D. v_(i) > v_(a) , v_(u) > v_(a)

Sound waves of wavelength lamda travelling in a medium with a speed of v m/s enter into another medium where its speed is 2v m/s. Wavelength of sound waves in the second medium is