An energy-efficient lamp rated at 10 watts uses 10 joules of energy every second (because 1 watt means using one joule per second), so it would take it 37,800 secondsâabout 10.5 hoursâto use as much energy as our kettle uses in a single boil!
raâ¢diâ¢us. 1. a straight line extending from the center of a circle or sphere to the circumference or surface: The radius of a circle is half the diameter. 2. the length of such a line. 3. any radial or radiating part.. A line segment that joins the center of a circle or sphere with any point on the circumference of the circle or the surface of the sphere. It is half the length of the diameter. 2.
Rating Newest Oldest. Best Answer: This is an ancient symbol called a triquetra (pronounced tri-KET-ra) which is latin for three-cornered. Nobody knows for sure, but a three-cornered symbol has appeared in many cultures throughout the world, the earliest example being from 5000 year old Indian artifacts.