Answer:
The f-ratio describes the relationship between the lens diameter and the focal length and is calculated by dividing the focal length by the diameter of the lens. For example, if a lens were to have a focal length of 50mm and a diameter of 10mm, then the f-ratio would be 50mm/10mm=5 or otherwise referred to as f5.
Explanation:
Total distance covered = 384 Km
Total time taken to travel from A to B = 8 hours [from 8 am to 4 pm, there are 8 hours]
We know, Average speed = Total Distance Travelled/ Total Time Taken
Therefore, average speed = 384 Km/8 h = 384000m/8×60×60s =(384000/28800)m/s
= 13.3 m/s
Answer is 13.3 m/s