2023 · Q71
Two lenses of powers +2.0 D and –2.5 D are combined to make an optical instrument. The combination will
General SciencePhysics
- Aact as a convex lens
- Bact as a concave lens
- Cact as a simple mirror
- Dnot form any image
Explanation
Powers add algebraically: +2.0 D + (-2.5 D) = -0.5 D. A negative power means a diverging lens, i.e. a concave lens. Hence B.