Question

why lens it is considered sometime positive and sometimes negative
​

Answer 1

after reflection the image will be formed or observed at a point because of the image position the lens is considered as positive or negative.

Answer 2

$\huge{\mathcal\red{♡Answer:}}$

A diverging lens is said to have negative focal length. A diverging lens causes exiting rays to be more divergent coming out than thay were enetering the lens. A converging lens can form a real image or a virtual image of a real object.

$<marquee>  ❤♥❤ I hope you will be helped by this answer. ❤♥❤   </marquee>$

$<marquee>  ♥❤♥ Please follow me and mark as brainliest. ♥❤♥  </marquee>$