Question

Two lenses of power +2.50 D and -3.75 D are
combined to form a compound lens. Its focal length
in cm will be
explain also

Answer 1

Hey mate!!!!!!

Power1= +2.5D

Power2= -3.75D

Therefore combined power = P1 + P2 = 2.5+ -3.75 = -1.25

Since Power = -1.25

P =1/f in metre

-1.25 = 1/f in m

f in m = -1/1.25

= -100/125

= -4/5

=-0.8m

f in m= -0.8m

f in cm = -0.8×100

= - 80 cm

Hope it helped you

Please mark it as the brainliest answer

Answer 2

Answer:

-80

Explanation:

Power1= +2.5D

Power2= -3.75D

Therefore combined power = P1 + P2 = 2.5+ -3.75 = -1.25

Since Power = -1.25

P =1/f in metre

-1.25 = 1/f in m

f in m = -1/1.25

= -100/125

= -4/5

=-0.8m

f in m= -0.8m

f in cm = -0.8×100

= - 80 cm

Hope it helped you

Please mark it as the brainliest answer