Using the lens maker's formula, f = R/2(n-1). Here, R = 10 cm, n = 1.5, so f = 10/(2(1.5-1)) = 10/1 = 10 cm.

Using the lens maker's formula, the focal length is calculated to be 20 cm.

Using the lens maker's formula, f = R/(n-1) = 30/(1.5-1) = 30/0.5 = 60 cm.

Using the lens maker's formula, the focal length is calculated to be 15 cm.

Using the lens formula, 1/f = 1/v - 1/u, we find v = 8 cm.

Using the lens formula, the image distance is calculated to be -16.67 cm.

Power (P) = 1/f (in meters). f = 20 cm = 0.2 m, so P = 1/0.2 = 5 D.

Using the lens formula 1/f = 1/v - 1/u, we have 1/(-10) = 1/v - 1/5. Solving gives v = -3.33 cm.

Using the lens maker's formula, f = R/(n-1), we find f = 20/(1.5-1) = 40 cm.

Using the magnification formula, m = h'/h = -v/u. Here, h' = 5 cm, v = 40 cm, u = -20 cm. Thus, h = (h' * u) / v = (5 * -20) / 40 = 2.5 cm.

Using the lens formula 1/f = 1/v - 1/u, we have 1/f = 1/15 - 1/60. Solving gives f = 10 cm.

Using the lens formula and magnification, we find the focal length to be 15 cm.

A virtual image is formed by a concave lens when the object is placed within its focal length.

Using the lens formula, 1/f = 1/v - 1/u, we find f = 4 cm.

Using the lens formula 1/f = 1/v - 1/u, where v = -20 cm and u = -10 cm, we find f = 5 cm.

A virtual image formed by a lens indicates that it is a concave lens.

A negative focal length indicates that the lens is a concave lens.

Using the lens formula, we find the image distance to be 40 cm.

Since the object distance is greater than the focal length, a real and inverted image is formed.

Power (P) = 1/f (in meters), so f = 1/2.0 = 0.5 m = 50 cm.

Power (P) = 1/f (in meters). Therefore, f = 1/2.5 = 0.4 m = 40 cm.

Power (P) = 1/f, so f = 1/P = 1/2.5 = 0.4 m.

Power (P) = 1/f (in meters). Therefore, f = 1/P = 1/5 = 0.2 m = 20 cm.

A negative power indicates a concave lens.

A negative power indicates that the lens is a concave lens.

Magnification (m) = h'/h, thus h' = m * h = 3 * 2 = 6 cm.

A virtual image is formed by a concave lens when the object is placed in front of it.

Using the lens formula 1/f = 1/v - 1/u, we find v = 20 cm.

For a concave lens, the image formed is virtual and erect when the object is placed in front of it.

Using the lens formula, the image is formed at 30 cm on the opposite side.