How long does it take a earth to rotate on its axis?

Your target variable is δf, the magnitude of the difference in frequency between the waves emitted from the sonar device and the waves received by the device after reflecting off the whale. write an expression for δf in terms of the relevant frequencies using the subscript notation introduced above.

Could someone . i have tried to solve myself but my calculation is off

Which of the following types of electromagnetic radiation has the longest wavelength? a. infrared light b. visible light c. ultraviolet light d. microwaves