1. Materials that allow light to pass but through which objects cannot be clearly seen are said to be   translucent   transparent   opaque   Hint Half-n-half Clue   2. A lunar eclipse occurs when the earth comes between the sun and the moon.   True   False   3. The SI unit of luminous intensity is _______.   Calorie   Candela   Coulomb   Half-n-half Clue   4. Illuminance of a surface is proportional to the power of the light source and inversely proportional to the square of the _______.   luminous intensity   area   distance   Half-n-half Clue   5. Light always travels in straight lines.   True   False   6. If the power of a light source is measured in candelas and distance in meters, then the illuminance of the surface is in   Lux   Joule   Watt   Half-n-half Clue   7. A _______ beam is one whose rays remain the same distance apart.   convergent   divergent   parallel   Half-n-half Clue