What is a compound microscope? A. A microscope that has one lens. B. A microscope that has two sets of lenses : an occular lens and an eyepiece. C. A microscope whose lenses are concave. D. A microscope whose lenses are convex.

The correct answer is: B. A microscope that has two sets of lenses : an occular lens and an eyepiece.

A compound microscope is a type of microscope that uses two sets of lenses to magnify an image. The first set of lenses, called the objective lenses, are located near the object being viewed. The second set of lenses, called the eyepiece lenses, are located near the eye of the viewer. The objective lenses magnify the image of the object, and the eyepiece lenses magnify the image further. This allows compound microscopes to magnify objects up to 2,000 times their actual size.

Option A is incorrect because a microscope that has one lens is called a simple microscope. Simple microscopes can magnify objects up to 10 times their actual size.

Option C is incorrect because a microscope whose lenses are concave is called a concave lens. Concave lenses are used to correct nearsightedness.

Option D is incorrect because a microscope whose lenses are convex is called a convex lens. Convex lenses are used to correct farsightedness.