a) The image formed in front of the concave mirror is real, so m is negative,

m = -3, u = -10 cm

As m = -v/u or -3 = -v/-10

v = -30 cm

By mirror formula,

1/f = 1/v + 1/u = 1/-30 + 1/-10 = -4/30

or f = -30/4 = -7.5 cm

Radius of curvature, R = 2f = 2 x (-7.5) = 15cm

a) The image formed in front of the concave mirror is real, so m is negative,

m = -3, u = -10 cm

As m = -v/u or -3 = -v/-10

v = -30 cm

By mirror formula,

1/f = 1/v + 1/u = 1/-30 + 1/-10 = -4/30

or f = -30/4 = -7.5 cm

Radius of curvature, R = 2f = 2 x (-7.5) = 15cm

the above answer is wrong pls check it

### Asked by prithivan2005 | 3rd Apr, 2020, 02:33: PM

a) The image formed in front of the concave mirror is real, so m is negative,

m = -3, u = -10 cm

As m = -v/u or

-3 =- v/-10

v = -30 cm

By mirror formula,

Thus, focal length of concave mirror is 7.5 cm.

Thus, Radius of curvature, R = 2f = 2 x (-7.5) = **- 15cm**

### Negative sign indicates that the mirror is concave mirror.

### Answered by Shiwani Sawant | 3rd Apr, 2020, 03:33: PM

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