1. Bodies that radiate light are called   luminous   non-luminous   opaque   Hint Half-n-half Clue   2. Materials through which objects can be seen clearly are said to be   opaque   transparent   translucent   Half-n-half Clue   3. Materials that allow light to pass but through which objects cannot be clearly seen are said to be   transparent   opaque   translucent   Half-n-half Clue   4. _______ is an instrument used to compare the luminous intensities of two sources of light.   Camera   Photometer   Electroscope   Half-n-half Clue   5. If the power of a light source is measured in candelas and distance in meters, then the illuminance of the surface is in   Lux   Watt   Joule   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 _______.   luminous intensity   area   distance   Half-n-half Clue   7. Materials through which light cannot pass are said to be   transparent   translucent   opaque   Half-n-half Clue