Assessment for learning

Assessment for learning

LO

• 12.1.1.7 - understand that information may be carried by a number of different channels: wire-pairs, coaxial cables, radio and microwave links and optic fibres;

  
  

  12.1.1.5 - recall the advantages of the transmission of data in digital form, compared to the transmission of data in analogue form;

  
  

  discuss the relative advantages and disadvantages of channels of communication in terms of available bandwidth, noise, cross-linking, security, signal attenuation, repeaters and regeneration, cost and convenience

Multiple Choice

The signal may be transferred in various ways using different channels of the communication EXCEPT

• wire-pairs

• optic fibres

• coaxial cables

• infra-red cables

Multiple Choice

In modern communications, wire-pairs are used mainly for very __________ distances with _________ frequencies.

• short, high

• short, low

• long, high

• long, short

Multiple Choice

Wire- pairs is used by linking telephones to the nearest exchange.

• TRUE

• FALSE

Multiple Choice

For wire-pairs, following difficulties might be occurred EXCEPT

• Energy is lost as heat in the resistance of the wires and also as radiation

• The wires easily pick up external interference and noise that degrades the original signal

• Low attenuation of the signal

• If high frequency signals are transmitted along a pair of wires over an appreciable distance, repeated amplification must be provided at regular intervals

Multiple Choice

Scenario 1: You can hear another telephone conversation

Above scenario gives very poor security as it is easy to ‘tap’ a telephone conversation. This effect is known as

• cross stitch

• cross-talk

• diffraction

• electromagnetic induction

Multiple Choice

The diagram shows a

• coaxial cable

• optic fibres

• microwave link

• radio link

Multiple Choice

For long distance communication using coaxial cables, _______________ can be arranged further apart.

• repeater generators

• repeater amplifiers

Multiple Choice

A pair one wire is shrouded by the other

• Wire-pairs

• Coaxial cable

Multiple Choice

Coaxial cable often connects a radio transmitter to an aerial

• TRUE

• FALSE