Penjelasan:

Given, the object distance (u) = 20 cm and the focal length (f) = 10 cm of a convex lens.

a. Image distance:

The formula to calculate the image distance (v) is given by 1/v - 1/u = 1/f, where u, v and f are the object distance, image distance and the focal length of the lens, respectively.

Using this formula, we can find the image distance (v):

1/v - 1/20 = 1/10

Solving for v, we get:

v = -10 cm

The negative sign indicates that the image is virtual, erect and on the same side of the lens as the object.

b. Magnification of the image:

The magnification (m) of the image is given by the ratio of the height of the image to the height of the object, and it can be calculated using the formula m = h_image / h_object = v/u.

m = -10/20 = -0.5

The negative sign indicates that the image is inverted.

c. Power of lens:

The power of a lens is defined as the reciprocal of its focal length in meters, and it is measured in diopters (D). The formula to calculate the power of a lens is given by P = 1/f.

In this case, the power of the lens is:

P = 1/10 cm = 10 D

d. Characteristics of image:

The image formed by the convex lens is a virtual, erect and inverted image. The image distance is -10 cm, which means the image is located on the same side of the lens as the object. The magnification of the image is -0.5, which indicates that the height of the image is half of the height of the object.