An object 4 cm in height, is placed at 15 cm in front of a concave mirror of focal length 10 cm. At what distance from the mirror should a screen be placed to obtain a sharp image of the object. Calculate the height of the image.

An object 4 cm in height, is placed at 15 cm in front of a concave mir

1.	An object 4 cm in height, is placed at 15 cm in front of a concave mirror of focal length 10 cm. At what distance from the mirror should a screen be placed to obtain a sharp image of the object. Calculate the height of the image.
Answer» Solution :Here distance of object u = - 15 cm, height of object h = +4 cm and the focal length of CONCAVE mirror f = - 10 cm. As per mirror formula `(1)/(v) + (1)/(u) = (1)/(f)`, we have `(1)/(v) = (1)/(f) - (1)/(u) = (1)/((-10)) - (1)/((-15)) = - (1)/(30) RARR v = - 30` cm. Thus, a screen be placed infront of mirror at a distance of 30 cm from it. `because` magnification `m = (h.)/(h) = - (v)/(u)` `therefore ""h. = - (v)/(u) xx h = - ((-30))/((-15)) xx 4 = - 8` cm Thus, image is an inverted image of height 8 cm.