Observation

This question was extremely difficult for the candidates as they could not provide
                        the required responses to the various parts of the question.  The required responses
to the various parts of the questions are:

 

(a)       

(i)         The component is a spark plug.

(ii)        The two types of the component are:
-           hot or long reach plug
-           cold or short reach plug.

 (iii)       The parts labelled are:

P          -           terminal
Q         -           centre electrode
R         -           earth electrode
S          -           thread reach.

(b)        The function of the component (spark plug) is to introduce a high-voltage
electric spark to ignite the compressed mixture of petrol and air in
the combustion chamber of the engine cylinder.

 

(c)        (i)   -  The contact breaker is a type of mechanical switch which breaks the primary (low voltage) circuit and induces a high voltage to the secondary winding which causes the coil to produce a high voltage current.
-           It controls the timing of the spark to the spark plugs.

 

             (ii)        Condenser:  

-           it stores electrical energy;
-           it prevents the burning or arcing of the contact points;
-           it also absorbs and retains fluctuation of electrical current in a circuit.

             (iii)       Connecting Rod:  

-           it is used to connect the piston to the crankshaft;
-           it transfers the force of the expanding gases from the piston
to the crankshaft.

              (iv)       Camshaft: 

-           it is used to open the engine valve at the correct time;
-           it drives the distributor, oil pump and mechanical fuel pump;
-           the camshaft is used to open the valve at the correct time;
hold it open for the correct time in relation to the movement of the piston.

 

(v)        Seat belt: 

-           it is used to reduce the likelihood of death or serious injury in a traffic collision.
-           A seat belt or safety belt is a safety device designed to secure the occupant of a vehicle against harmful movement that may
result during a collision or sudden stop.