A car passing a check post gives sound of frequency 1000 c.p.s. If the velocity of the car is `72km//h` and of sound is `350m//s` , find the change is apparent frequency as it crosses the post.

A source of sound is travelling with a velocity 40 km/h towards an observer and emits a sound of frequency 2000 Hz. If the velocity of sound is 1220 km/h, then the apparent frequency heard by the observer is. …………………

A car is travelling with a velocity of 40 m//s towards a source of sound of frequency 1000 Hz. If sound velocity is 330 m//s , then apparent frequency heard by the observer (in Hz) is

A train is moving with a uniform speed of 33 m//s and an observer is approaching the train with the same speed. If the train blows a whistle of frequency 1000 Hz and the velocity of sound is 333 m//s then the apparent frequency of the sound that the observer hears is

A train is moving with a uniform speed of 33 m/s and an observer is approaching the train with the same speed. If the train blows a whistle of frequency 1000 Hz and the velocity of sound is 333 m/s, then the apparent frequency of the sound that the observer hears is

A car is moving along X-axis with a velocity v=20m//s . It sounds a whistle of frequency 660 Hz. If the speed of sound is 340m//s . The apparent frequency heard by the observer O (shown in figure) is: