1. Illuminance of a surface is proportional to the power of the light source and inversely proportional to the square of the _______.   area   distance   luminous intensity   Hint Half-n-half Clue   2. _______ is a type of solar eclipse where the moon's shadow covers the sun's center and has a ring of sunlight around it.   A lunar eclipse   An annular eclipse   A helical eclipse   Half-n-half Clue   3. A _______ eclipse occurs when the moon comes between the sun and the earth.   lunar   solar   4. Light always travels in straight lines.   True   False   5. If the power of a light source is measured in candelas and distance in meters, then the illuminance of the surface is in   Joule   Lux   Watt   Half-n-half Clue   6. The SI unit of luminous intensity is _______.   Candela   Coulomb   Calorie   Half-n-half Clue   7. The solar eclipse occurs more frequently than the lunar eclipse.   True   False