An object is placed 40 cm from a lens of focal length 56 cm

An object is placed 40 cm from a lens of focal length +56 cm. Describe the image. real, inverted, and diminished real, inverted, and enlarged virtual, inverted, and diminished virtual, upright, and diminished virtual, upright, and enlarged

Solution

the image distance is,

    1/q = 1/f - 1/p

          = 1/56 - 1/40

          = -0.007142

   q = - 139.99 cm = - 140 cm

the image distance has negative sign.

so image is virtual.

since the image distance is negative, so the magnification is

m = -q/p is positive. therefore, the image is virtual, upright, and enlarged.