1 An 20 cm high object is placed in front of a converging le

1.) An 2.0 cm high object is placed in front of a converging lens. A real image forms that is 4.0 cm in height. Which of the following describes the magnification and orientation of the image?

a. Magnification is 0.5; image is inverted.

b. Magnification is 2.0; image is inverted.

c. Magnification is 4.0; image is inverted.

d. Magnification is 4.0; image is upright.

e. Magnification is 2.0; image is upright.

f. Magnification is 0.5; image is upright.

2.) An object is located a distance of 8 cm from a thin converging lens having focal length 10 cm.  The image of the object is

a. real, upright, and smaller than the object.

b. real, inverted, and smaller than the object.

c. real, inverted, and larger than the object.

d. virtual, upright, and smaller than the object

e. virtual, inverted, and larger than the object.

f. virtual, upright, and larger than the object.

Solution

According to the given problem,

1.) The magnification is given by M = h_i/h_o = 4/2 = 2

As it is a converging lens image is inverted [b]

2.) Using the basic lens equation:

1/p + 1/q = 1/f where p(object distance) = +8cm

q(image distance), f(focal length) = + 10 cm

1/8 +1/q = 1/10

q = -40 cm

The magnification is given by M = -d_i/d_o= -(-40)/8 = 5

As it is a converging lens image formed is real, inverted, and larger than the object. [c]