A 3.92 cm tall object is placed in 31.3 cm in front of a convex mirror. The focal
length is 12.7 cm. What is the magnification of the image?

0.29

Explanation:

We can find the position of the image by using the mirror equation:

where:

f is the focal length of the mirror

p is the distance of the object from the mirror

q is the distance of the image from the mirror

For the mirror in this problem:

f = -12.7 cm (the focal length of a convex mirror is negative)

p = 31.3 cm (distance of the object)

Solving for q, we find the position of the image:

And so, the magnification of the image is:

And substituting,

Which means that the image is upright (positive sign) and diminished (M is smaller than 1).

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