Question

what do astronomers use to break a stars light into a spectrum?
spectrograph
prism
mirror
lens

Explanation:

A spectrograph is an instrument that can break a star's light into a spectrum, analyzing its different wavelengths. A prism can also disperse light into a spectrum. Mirrors and lenses are mainly for reflecting and refracting light, not specifically for creating a spectrum of star - light.

Answer:

A. spectrograph, B. prism