Question

plz, answer the following questions only 2nd and 3rd one,,
and explain it too​

Answer 1

Answer:

here

Explanation:

Q2) answer= Object distance, u= – 50 cm

Image distance, v= 50 cm

Focal length = f

According to the lens formula,

u = -50 cm v = + 50 cm. f =? 1/f = 1/v €“ 1/u 1/f = 1/50 + 1/50 f = + 25 cm. = 0.25 m Power of lens (P) = 1/f = 1/ 0.25 = + 4D

Q3) answer= A concave lens has negative focal length, so it is to be written with a minus sign. Thus,

Focal length, f=−2 m

Now, Power, p=1f in metres

P=1−2

P=−0.5D

Thus, the power of this concave lens is, −0.5 dioptre.