An object is placed at 60 cm from the pole of a concave mirror with focal length of 20 cm. Find the distance at which the image is formed.​

Sure, to find the distance at which the image is formed, we can use the mirror formula which is 1/f = 1/v + 1/u.

Here, f = focal length = -20 cm (it's negative because for a concave mirror, the focus is on the same side as the light source) u = object distance = -60 cm (it's negative because the object is on the same side as the light source)

Substituting these values into the formula, we get:

1/-20 = 1/v + 1/-60

Solving this equation for v (the image distance) gives us:

1/v = 1/-20 - 1/-60

1/v = -3/60 + 1/60

1/v = -2/60

Therefore, v = -60/2 = -30 cm

So, the image is formed 30 cm from the pole of the mirror on the same side as the light source. The negative sign indicates that the image is virtual and formed on the same side as the object.