Electricity Paper 2 Questions and Answers - KCSE 2022 Prediction

INSTRUCTIONS TO CANDIDATES

• Non-programmable silent electronic calculators are allowed for use
• This paper consists of 5 EXERCISES
• Each exercise should be done in 30 MINUTES

Questions

EXERCISE 1

Using the components, materials and equipment provided, perform the following tasks

1. Connect the figure as shown below. Let the examiner check your work (6 marks)
   
2. Close the switch. Adjust the potentiometer to obtain voltage reading shown in the table below. For each voltage obtained, measure and record the corresponding current values (5 marks)
   

   Voltage(V)	0	0.5	0.7	0.9	1.3	1.7
   Current(mA)

3. Plot a graph of current against voltage. (6 marks)
4. From the graph
   1. Determine the resistance when the voltage is 1.3V
   2. Give a reason for the shape of the graph (3 marks)

EXERCISE 2

Using the components, materials and equipment provided, carry out the following tasks:

1. Connect the circuit as shown in the figure below
   
   Let the examiner check your work. (5 marks)
2. Adjust Vcc to the values shown in the table below and for each voltage value measure and record the corresponding value of the collector current, Ic (6 marks)
   

   Vcc	9	7	5	3	1	0.5
   Ic(mA)

3. Repeat step in (b) above for the values shown in the table below and complete the table
   

   Vcc	10	8	6	4	2	0.5
   Ic(mA)

   
   From the results obtained in (b) and (c) above, make two comments about the collector current Ic. (4 marks)
4. State two factors that determine the value of collector current (2 marks)

EXERCISE 3

Using the tools, materials and equipment provided, carry out the following tasks:

1. Terminate the three-core flexible cable to the top plug and iron box (15 marks)
2. Turn the thermostat switch to ON position, measure and record the values of resistance between;
   1. Live and Neutral at plug………Ohms
   2. Live and earth at plug………...Ohms
   3. Earth at plug and iron box body……..Ohms
   4. Neutral at plug and at iron box……….Ohms
      (5 marks)

EXERCISE 4

Using the tools, material and equipment provided, fabricate the stand as shown in the figure below. (20 marks)

EXERCISE 5

The figure below shows the layout of a final circuit. Using PVC sheathed cables, install the lamps to controlled by one-way switch (20 marks)

Confidential

Marking Scheme

EXERCISE 1

EXERCISE 2

EXERCISE 3

EXERCISE 4

EXERCISE 5