Answer:
Where speed limit of speed camera is 50 km/h.
Explanation:
Speed cameras work on the principal that photos reflected from the moving car have a higher or lower frequency. This is the Doppler principal. In a car traveling at the speed of light, the waves/particles will not be able to catch up with that car thus no photon will reflect back to the receiver/speed camera thus no speed will be record. Such a speed is impossible to achieve due to the amount of infinite energy expenditure required. This means if the speed is higher and approaching that of light, the frequency of reflected photons will be very high causing high amounts of energy that could damage the speed camera and cause detection. When the car travels at a higher speed, the photos frequency is high thus more energy they will carry and high chances of the vehicle being detected. This means the time interval of photos taken will be smaller.