IGCSE Computer Science Paper-1: Specimen Questions with Answers 135 - 137 of 164

Explanation

There are many specialised softwares used to carry out video-conferencing. The most popular among them is Skype. Skype is defined as the voice over Internet Protocol (VoIP) software application. This can be successfully used for voice, video and instant messaging communications. The software also allows user to make calls, video calls or engage in chat over the Internet.

One of the advantages of Video Conferencing is that it saves time and it can be conducted over large distances.

The disadvantage is that due to time zone differences, the meetings over Video-Conferencing gets interrupted.

Explanation

There are five types or Classes of Network:

i) Class A-0.0.0.0 to 127.255.255.255

ii) Class B-128.0.0.0 to 191.255.255.255

iii) Class C-192.0.0.0 to 223.255.255.255

iv) Class D-224.0.0.0 to 239.255.255.255

V) Class E-240.0.0.0 to 247.255.255.255

Explanation

Virtual Reality is defined as the artificial environment being created by software and presented to the user in such a way that user takes it as a real environment.

i) In Computers virtual reality is experienced through sight and sound.

ii) Liquid Crystal Display (LCD) Screen is one of the most common types of virtual reality.

iii) There are four types of virtual reality immersive virtual reality, desktop virtual reality, Projection virtual reality and simulation virtual reality.

iv) At present Games, surgery and flight simulators are the most well-known uses of virtual reality.