Correct Answer: Option B

Explanation

if r = 40 cm , then f = r/2 = 40/2 = 20 cm
then for a real image by a concave mirror,
magnification M = f/u-f => 2 = 20/U-20
therefore 2(u-20) = 20
2u - 40 = 20
2u = 40 + 20
2u = 60/2 = 30 cm

• If the power of a lens is +2.5D. Calculate the radius of curvature (a). 80cm (b). 40cm (c). 25cm (d).... Answer this

  1 Answers   ·   Physics   ·   3 days ago
• Subjects to learn under petroleum engineering? Answer this

  1 Answers   ·   3 days ago
• what is the cut of mark for medical doctor in university and list all the university? Answer this

  1 Answers   ·   1 day ago