Question 1
- With the aid of a sketch, show the connection of a six cell battery in series to three lamps.
- List six components of a lead-acid battery.
(c) State the condition of a lead-acid battery cell when the battery is:
(i) charged;
(ii) discharged.
(d) State three safety precautions that should be taken when mixing electrolyte.
Observation
The expected answers were;
- Sketch showing the connection of a six-cell battery in series connection to three lamps
Components of a lead-acid battery
- Container/protective casing
- Separators/cell divider
- Electrolyte/dilute sulphuric acid
- Plates
- Grids
- Cell covers/plastic cover
- Cell connectors
- Cells
- Positive terminal/post
- Negative terminal/post
- Sealing components
- Indicator
- Vent plug
(c) (i) Condition of lead-acid battery cell when charged
- Positive plate becomes lead peroxide and negative plate becomes spongy lead.
- Cell produces the required voltage.
(ii) Condition of lead-acid battery cell when discharged
- Both positive and negative plates become lead-sulphate/sulphation of cells/white crystal material deposit on cells.
- Cell does not produce the required voltage.
(d) Safety precautions that should be taken when mixing electrolytes.
- Always add acid to water and not the reverse.
- Electrolytes should be mixed in non-corrosive container.
- Electrolytes should be mixed in a well ventilated environment.
- No naked light in a mixing room should be allowed.
- Ensure the use of leather aprons when mixing electrolytes.
- Ensure the use of rubber hand gloves.
- Wear safety goggles.
- Wear safety boots.
To obtain maximum mark in the (a) part, candidates were required to draw: correct symbol of 6 cells in series; correct symbol of 3 lamps either in series or in parallel; connecting wires. Majority of the candidates that attempted question one responded quite satisfactorily.