For a machine to be a heat engine, what kind of conversion must it perform? a. work into heat b. heat into entropy c. entropy into heat d. heat into work !

Aspectroscope breaks light up into its colors, allowing scientists to analyze light from the solar system and universe. by studying the spectral line patterns, widths, strengths and positions, scientists can determine the speed, position, and of celestial bodies. a) age b) origin c) rotation d) temperature