Answer:
(a) convex mirror
(b) virtual and magnified
(c) 23.3 cm
Explanation:
The having mirror is convex mirror.
distance of object, u = - 20 cm
magnification, m = 1.4
(a) As the image is magnified and virtual , so the mirror is convex in nature.
(b) The image is virtual and magnified.
(c) Let the distance of image is v.
Use the formula of magnification.
![m =-\frac{v}{u}\\1.4=-\frac{v}{-20}\\v =28 cm](https://tex.z-dn.net/?f=m%20%3D-%5Cfrac%7Bv%7D%7Bu%7D%5C%5C1.4%3D-%5Cfrac%7Bv%7D%7B-20%7D%5C%5Cv%20%3D28%20cm)
Use the mirror equation, let the focal length is f.
![\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\\\frac{1}{f}=\frac{1}{28}+\frac{1}{20}\\\frac{1}{f}=\frac{28+20}{560}\\f=11.67cm](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bf%7D%3D%5Cfrac%7B1%7D%7Bv%7D%2B%5Cfrac%7B1%7D%7Bu%7D%5C%5C%5Cfrac%7B1%7D%7Bf%7D%3D%5Cfrac%7B1%7D%7B28%7D%2B%5Cfrac%7B1%7D%7B20%7D%5C%5C%5Cfrac%7B1%7D%7Bf%7D%3D%5Cfrac%7B28%2B20%7D%7B560%7D%5C%5Cf%3D11.67cm)
Radius of curvature, R = 2 f = 2 x 11.67 = 23.3 cm