1. The solar eclipse occurs more frequently than the lunar eclipse.   True   False   2. If the power of a light source is measured in candelas and distance in meters, then the illuminance of the surface is in   Watt   Lux   Joule   Hint Half-n-half Clue   3. A _______ beam is one whose rays remain the same distance apart.   parallel   divergent   convergent   Half-n-half Clue   4. Light always travels in straight lines.   True   False   5. The SI unit of luminous intensity is _______.   Calorie   Candela   Coulomb   Half-n-half Clue   6. Illuminance of a surface is proportional to the power of the light source and inversely proportional to the square of the _______.   distance   area   luminous intensity   Half-n-half Clue   7. The partly lighted area of a shadow on the periphery of the totally shaded portion is called the _______   penumbra   umbra   eclipse   Half-n-half Clue