Observation

(a)       (i)        Open circuit: This fault occurs as a result of failure of one or more conductors in 
an electrical circuit leading to very high resistance value and zero current.
(ii)       Short circuit: This fault occurs when contact is made between two wires of different polarity (live and neutral) thereby leading to the flow of excessive current in the circuit.

(b) Measures that can keep electric blender in good working condition                                 

• Regular clean up with the use of vacuum cleaners to get rid of dirts.
• Periodic lubrication of electric motors that are not sealed.
• Appliance should be kept away from sources of heat (oven, fire, etc.)
• Ensure compliance with manufacturer’s instructions.
• Always start the blender from low to high variable speed.
• Do not submerge the motorized blender base in water.
• Rinse jar thoroughly with warm water after use and allow to dry before storage.
• Unplug the blender when cleaning and when not in use.
• Avoid overloading the jar with content(s) to be blended.

                                                                     
The few candidates who attempted this question did poorly.