This was a very unpopular question among the candidates.  The performance of those candidates who attempted it was very poor.

Back bearing refers to the angular bearing taken from the present station to the  previous one.

The procedures for compass traversing include:

• a conduct of the preliminary survey of the area
• determination of the stations
• marking of the stations with numbers or letters
• taking angular measurements to the nearest station
• measuring distances between stations
• taking off sets and bearings from the legs to the nearest reference objects
• recording all measurements and other observations in Field Notebook
• choosing a suitable scale for plotting
• plotting all measurements and observations.

•  some magnetic elements beneath or above the earth’s surface can influence the needle of the compass
• Wrist watches, hooks, or belts of magnetic materials can influence the reading of the needle of the compass
•  the carelessness of the surveyor
• tiredness of the surveyor
• reading the   bearing when the card is not stable
• physical defects such as bad eyesight
• damaged  instruments can give wrong reading
• a chain or tape that is not standard