Question

focal length of lens is +10 cm. focal length of B is -15 CM which is convex lens​

Answer 1

Answer:

15 is the correct answer

Explanation:

As we know,

f

1

=(μ−1)(

R

1

1

−

R

2

1

)

⇒

+10

1

=(1.5−1)(

+7.5

1

−

R

2

1

)⇒R

2

=−15 cm

Answer 2

A is a convex lens

positive values for focal length