What is the unit of luminous intensity?

A. Footcandle

B. Lumen

C. Candela

D. Lux

Which of the following is true about low-mass stars compared to high-mass stars?

• Low-mass stars have the same temperature and luminosity as high-mass stars.
• Low-mass stars are cooler but more luminous than high-mass stars.
• Low-mass stars are hotter but less luminous than high-mass stars.
• Low-mass stars are cooler and less luminous than high-mass stars.
• Low-mass stars are hotter and more luminous than high-mass stars.

Light is a form of energy produced by___

1. Luminous object.
2. Transparent object.
3. Non-luminous object.
4. Opague object.

Sirius is 22 times more luminous than the Sun, and Polaris (the "North Star") is 2,350 times more luminous than the Sun. Sirius appears 23 times brighter than Polaris. How much farther away from us is Polaris than Sirius? What is the distance of Polaris in light-years?