An object is placed in front of a lens which forms an image of the object.
a) if the lens is convex, the image cannot be virtual.
b) if the image is real, then it is also inverted.
c) if the image is real, then it is also upright.
d) if the image is virtual, the lens must be a diverging lens.
e) if the image is virtual, then it is also inverted.

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.