Wireless communication quiz#
According to How WiFi and Cell Phones Work | Wireless Communication Explained
Exercise 67 (Antenna)
Which of the following is wrong about antennas?
Earlier phones used long antennas called dipole antennas.
Nowadays cell phones do not need any antennas anymore thanks to the technological advances.
Radio waves sent by your mobile phone do not have a color.
An antenna converts electrical impulses to electrical and magnetic waves.
A Wi-Fi antenna can send about 2 billion beats per second.
Exercise 68 (Electromagnetic waves)
Which of the following is wrong about electromagnetic waves?
Electromagnetic waves are fluctuations in electromagnetic field.
An antenna radiates energy as electromagnetic waves.
Electromagnetic waves can be visible or unvisible.
An electromagnetic wave is created by the rhythmic move of electrons similar to when we touch a water surface and see a wave forming.
A rhythmic move can be created by using direct current, e.g., by applying 5V on an antenna.
Exercise 69 (Transmitting a message)
You send a message using your smartphone to your friend. Which of the following is wrong?
When you send a message on your messaging app, this message is transformed to a choreography of electron dance.
Your smartphone’s antenna could send the message directly to your friend’s smartphone who is in another continent, but this does not make sense, because your smartphone’s battery would drain quickly otherwise.
The electron dance causes on your smartphone’s antenna causes a similar dance in the cell tower, which in turn are transmitted over cables to its destination.
Your friend receives the message in a similar way like in the message transmission.
Exercise 70 (Smartphone - cell tower communication)
Which of the following regarding cell tower - smartphone communication is wrong:
Your phone does not need to have a line of sight to a cell tower, because electromagnetic waves can bend or be reflected around surfaces.
The message you send with your smartphone can be received by anyone in your proximity, but its content can only be read by people who know the key to decrypt your message.
The cell tower knows that you sent the message, because a cell tower’s antenna can distinguish exactly from which location the signal came. It tracks you from the moment you are visible to the cell tower and stores this information for tracking.
A receiver can differentiate transmitters by frequency, time, location and code differences.
You can best listen to one of your friends if one of them speaks at a time. This principle can also be used for a cell tower communicating with many phones.