Question

the length of astronomical telescope is 40 cm and magnifying power is 7 then the focal length is
a)+35cm and -5cm
b)-35cm and -5 cm
c)+35 cm and +5 cm
d)-35cm and +5cm
WITH REASON
correct ans will get 20 points​

Answer 1

Answer:

don't have reason but I think the right answer is b) -35cm and -5cm hope this will help