Questions

Compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony and released in 1982. 

These are actually made to replace floppy disks that were used to store files and programs from the computer.

The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM).ese CD's uses Laser technology.

In the periodic table, the atomic radius increases from top to bottom in the groups and it increases from right to left in the periods.

Francium is the atom with largest atomic radius. Helium is the atom with smallest radius.

EPA - Environmental Protection Agency.

The EPA estimates that 85% - 90% of the waste is recyclable, but we only recycle about 30% - 40% of it.

The resistance of metallic conductors e.g, platinum, increases with rise of  temperature . The increase in temperature results in a decrease of current which can be recorded in a galvanometer if the conductor is included in an electrical circuit. Thus the temperature can be known; platinum resistance thermometer is used generally for accurate scientific work. When two dissimilar metals are joined at the ends, and these ends are subjected to a difference of temperature, a current flows through the metals. Greater the difference of temperature , greater the current. So the curent strength can form the basis for measuring the difference in temperature. And when one of these temperatures is known, we can calculate the other.