Practice question

**Spherical mirror reflection** follows law θ_i = θ_r, focal length f = R/2, concave R negative, convex positive. Object beyond center C (u > 2f) forms image between F and C diminished, at C same size, between C and F magnified, beyond F forms at infinity, illustrating mirror equation. Focal length: f = (R/2) = (-40/2) = -20 cm . Object distance: u = -25 cm . Mirror equation: (1/v) + (1/-25) = (1/-20) ⇒ (1/v) = (1/-20) + (1/25) = (-5 + 4/100) = (-1/100) . v = -100 cm . Substituting values gives 100 cm, which matches expected image position and magnification from