The magnification produced by a spherical mirror and a spherical lens is + 0.8.(a) The mirror and lens are both convex (b) The mirror and lens are both concave(c) The mirror is concave but the lens is convex (d) The mirror is convex but the lens is concave

Explanation

1. Here, the magnification produced by a spherical lens and a spherical mirror has a plus sign (+0.8), and we know that if the magnification $m$ has a plus sign $(+)$ then the image formed is virtual and erect.

2. Also, the magnification produced (here, 0.8) is less than 1, which implies that the image formed is smaller than the object (diminished).

Now, considering the two points given above we can conclude that the image formed will be virtual, erect, and diminished (smaller than the object). And, this type of image is only produced by a convex mirror and a concave lens.

Thus, if the magnification produced by a spherical lens and a spherical mirror is +0.8, then the mirror will be convex but the lens will be concave.