To focus X rays, such as those collected in the Chandra X–Ray Observatory, it is necessary to use a. a lens. b. a concave glass mirror, such as that used in an optical reflecting telescope. c. a metal dish, such as that used in a radio telescope. d. grazing incidence optics shaped like a converging, hollow tube. e. a mesh of conducting wires.

To focus X rays, such as those collected in the Chandra X–Ray Observatory, it is necessary to use a. a lens. b. a concave glass mirror, such as that used in an optical reflecting telescope. c. a metal dish, such as that used in a radio telescope. d. grazing incidence optics shaped like a converging, hollow tube. e. a mesh of conducting wires.

	a.	a lens.
	b.	a concave glass mirror, such as that used in an optical reflecting telescope.
	c.	a metal dish, such as that used in a radio telescope.
	d.	grazing incidence optics shaped like a converging, hollow tube.
	e.	a mesh of conducting wires.