Question

3. If tangents PA and PB from a point P to a circle with centre o are inclined to each other
at angle of 80º, then Z POA is equal to
(A) 50
(B) 60°
(C) 70°
(D) 80°
​

Answer 1

Answer:

c is the correct answer

Answer 2

Step-by-step explanation:

Given,

Radius of curvature, R=40cm

Object distance, u=30cm

Object height, h

o

=3cm

The focal length of the mirror=f=−

2

R

=−20cm

From mirror equation,

v

1

+

u

1

=

f

1

⟹

v

1

+

−30

1

=

−20

1

⟹v=−60cm

The magnification, M=

u

−v

=−

−30

−60

=−2

Hence the image is inverted, enlarged, real and its size is 2×3cm=6cm