In concave mirror, the size of image depends upon

The location of the object relative to the vertex, V, the focus, F center of curvature, C and infinity

Explanation:

The location of the object relative to the vertex, V, the focus, F center of curvature, C and infinity such that;

The image of an object placed at V, touching the mirror is the upright and the same size as the object and virtual

The image of an object placed between V and F is upright and magnified also virtual

The image of an object placed at the focus is at infinity

The image of an object placed between C and F is real, magnified and inverted

The image of an object placed at C is real, same size and inverted

The image of an object placed between C and infinity is real, diminished and inverted

The image of an object placed at infinity is size zero and real.

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

d eras and periods