An object is placed 20cm from a concave mirror of focal length 15cm. Calculate the linear magnification of the image formed

The linear magnification of an image formed by a spherical mirror is given by the formula: magnification = height of image / height of object = -v/u where u is the object distance, v is the image distance and the negative sign indicates that the image is inverted. Given that the object is placed 20cm from a concave mirror of focal length 15cm, we can use the mirror formula: 1/f = 1/u + 1/v Rearranging this formula, we get: 1/v = 1/f - 1/u Substituting the given values, we get: 1/v = 1/15 - 1/20 1/v = (4 - 3)/60 1/v = 1/60 v = 60 cm Now, the magnification can be calculated as: magnification = -v/u = -60/20 = -3 Therefore, the linear magnification of the image formed is 3. Since the image is inverted, the sign of the magnification is negative. So, the correct answer is (d) 3.0.