Sound is described as disturbance in a medium. So even if there is no one to hear it at that moment, there will be evidence of the fact for any future observer and it can be called as sound.
I am a 4 digit number My 1st digit is of no use as I still remain same without it. My 2nd and 3rd digits are mirror images. My 4th digit are half of 2nd. Can you guess the number ?
Two jets take off at the same time. There is only one runway but there where no crashes and it was at the same airport. A plane takes more than one minute to take off. How can this happen?
