A police car's radar gun emits microwaves with frequency f. 1. =36 GHz. The beam ... waves at f. 2 . • Which frequency is higher, f. 1 or f. 2 ? • Calculate the difference f. 2. – f. 1 . 2. Page 3 ... The Doppler effect for EM waves is derived in ... velocity between source and observer. 4 ... The reflected waves have this shifted.