An object is placed at a distance of 30 cm from a concave lens of focal length 30 cm.
(i) Use lens formula to determine the distance of the image from the lens.
(ii) List four characteristics of the image (nature, position, size, erect/inverted) in this case.
(iii) Draw a labelled diagram to justify your answer of part (ii).

Explanation

`u = -60cm, f = -30 cm`
(i) Lens formula, `1/f = 1/v - 1/u`
`1/v = 1/f +1/u`
`rArr 1/v=1/-30+1/-60=(2+1)/-60=3/-60`
`v=(-60)/3 =-20cm ` The image is at a distance of 20 cm from the lens.
(ii) Characteristics of image formed. The image is -
`{:(" vortual,", erect,", in front of the lens between 'O' and 'F',"),(" on the same side of the object, and ",""," diminished."):}`
(iii)