Physics 2 Marks Questions

www : It is the short form of 'Word Wide Web'. In it one computer share with the other 'computer'. Many search engines as (Google, Yahoo etc.) search website. By Hypertent on wepeze is linked with the other utility HTML itself.
Fax : It is the short name of facsimile. Figure of document is taken by one machine (Fax) and is send by telephone line on the other machine.

Range of transmission of T.V. signal can be increased by :
(i) Increasing the height of transmitter tower.
(ii) Increasing the height of receiver tower.

Frequency range of T.V. transmission is 80 MHz-200 MHz. For this transmission space wave transmission method is adopted.

Sky waves cannot be used in transmitting TV signals having frequencies 80 MHz or more, because these waves are not reflected back by the ionosphere and penetrate into the outer space.

MODEM : The word MODEM is a contraction of the terms modulator and demodulator i.e., Modem = Mod + dem which in brief is written as MODEM. Here the three letters MOD are taken from Modulator and the three letters DEM are taken from Demodulator. Thus MODEM is a single device in which both functions of modulation and demodulation can be carried out. In transmission action Modem is used as a modulator and in receiving action it is used as a demodulator. Thus, in a communication system one Modem set is attached with transmitter and another modem is attached with receiver.
A modem is also called data set because it connects the data source (i. e. computer etc.) with the transmitter or the receiver.

Actually transducer is a device which converts energy from one form to another. In communication system an electrical transducer is a device which converts variation in a physical quality such as pressure, displacement force, temperature etc. into corresponding variations in the electrical signal at its output. For example, Microphone, Photodetector etc.