1. As far as lenses are concerned, an object is considered to be a virtual object whenever

  a. the object distance is greater than the focal length.   b. the object distance is less than the focal length.  c. the light converges as it approaches the lens.       d. the light diverges as it approaches the lens. e. None of the above.

2. A converging lens is also sometimes called a positive lens because

  a. d_o > 0     b. d_i > 0     c. f > 0    d. R > 0   e. All of these.

3. The difference between the image distance, D_i, and the image position, d_i, is that

  a. the distance is always positive, whereas the position can be positive or negative.

  b. the position is always positive, whereas the distance can be positive or negative.

  c. the distance is measured to the right of the lens, but the position is measured to the left.

  d. the distance is measured to the left of the lens, but the position is measured to the right.

  e. There is no difference–they are two different terms for the same thing.

4. If the magnification of a lens is negative, then

  a. the image has the same orientation as the object.

  b. the image has an inverted orientation relative to the object.

  c. the image is real and the object is virtual.  d. the image is virtual and the object is real.

  e. both the image and object are virtual.

5. There are two good ways to find a description of an image in a lens.  One is to use the thin lens equation. The other is to use

  a. the lensmaker’s equation.   b. Snell’s law.  c. the law of refraction.

  d. a free-body diagram.  e. a ray diagram.