Question

how far from a concave mirror (radius 27.8 cm ) must an object be placed if its image is to be at infinity? express your answer to three significant figures and include the appropriate units.

Answer 1

The object distance from a concave mirror with a radius of 27.8 cm, when the image is at infinity, is 13.9 cm.

Step-by-step explanation:

To find the object distance (do) from a concave mirror with a radius of 27.8 cm when the image is at infinity, we can use the thin lens equation:

1/f = 1/d₀ + 1/di

In this case, since the image is at infinity, 1/di = 0:

1/f = 1/d₀

Substituting the value for the focal length (f = R/2 = 27.8/2 = 13.9 cm) into the equation:

1/13.9 = 1/d₀

Solving for d₀:

d₀ = 13.9 cm