What is the difference between 3G and WiFi Network?

One of the main differences between 3G and WiFI is the range of the network. If you would notice, WiFi will only cover a small space, so you need to be near the WiFi so that you can connect to the internet. When you use 3G, this means that you need to rely on your cellular phone so that you can connect to the internet. If you do not have data, you will not be able to connect. 3G is known to be effective in making sure that mobile phones are also connected.
Some people would usually connect to public WiFi whenever they get the chance so that they can connect to the internet, but this is not always advisable, especially when you do not want to have some of your personal data to be retrieved.