(1) According to the imaging rules of convex lenses and their applications: u>2f, an inverted and reduced real image is formed, which can be used in cameras and video cameras.
2f>u>f, forming an inverted magnified real image
(2) "F" replaces the candle in the experiment. Its size remains unchanged and the light source is relatively stable, which can avoid the candlelight. Shaking makes it easy to operate during experiments; it is more obvious to see that the image and object are also symmetrical.
So the answer is:
? The focal length of the convex lens f=10cm? What are the advantages of using "F" instead of a candle to do experiments? Experiment serial number? Object distance u/cm?
The nature of the image? Application 1. It can avoid the shaking of the candlelight and is easy to operate during the experiment;
2. It is more obvious that the image and the object are also symmetrical. ?1 ?30 ?Inverted, reduced real image?Camera?2?20?Inverted, equal-sized real image?Focus length?3?15?Inverted, enlarged real image??Projector?4?5?Erect, equal-sized Virtual image? Magnifying glass