d
explanation:
v=uf/(u-f)
= 5.10/(5-10) convex lens has positive focal length
=50/-5
=-10 cm (formed at other side)
5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000
the answer is mosques. they are an important part of islamic culture.