KCSE 2019 Electricity Paper 2 Questions with Marking Scheme

Electricity Paper 2 (4482)

EXERCISE 1

1.            
   1. Using the materials and equipment provided, connect the circuit shown in Figure 1 on a bread board. (3 marks)
      
      Let the examiner check your work.
   2. Close switch S, measure and record the values of the following quantities in Table (la).(4 marks)
      Table 1(a)
      

      	MEASURED VALUES
      Current I₁
      I₂
      Voltages V₁
      V₂

   3. Using the same materials provided in 1(a), connect the circuit shown in Figure 2. (3 marks)
      
      Let the examiner check your work.
   4. Close switch S and record the values of the following quantities in Table 1(b). (4 marks)
      Table 1(b)
      

      	MEASURED VALUES
      Current I₁
      I₂
      Voltages V₁
      V₂

   5. State the reason for the differences between measured values obtained in Table 1(a) and 1(b). (6 marks)

EXERCISE 2

2. Use the tools and materials provided to fabricate the electronic components tray shown in Figure 3. (20 marks)
   

EXERCISE 3

3. Using the tools, materials and equipment provided, carry out the following tasks:
   1. Terminate the top plug to a functional electric kettle. (12 marks)
   2. Measure and record values of resistance for each test conducted. Record your values in Table 2. (6 marks)
      Table 2
      

      MEASUREMENTS	RESISTANCE (Ohms)
      Live and neutral at plug
      Live and carth at plug
      Neutral and earth at plug
      Neutral at plug and kettle
      Live at plug and kettle
      Earth at plug and kettle

   3. Name the tests carried out in (b). (2 marks)

EXERCISE 4

4. Figure 4 shows a block diagram of the electronics circuit board provided
   Perform the following tasks:
   1. With switch S open, connect the circuit to the cquipment as follows:
      1. P and Q to 9 volts D.C. power supply.
      2. A and B to a voltmeter
      3. Y and Z to an ammeter. (3 marks)
         Let the examiner check your work.
   2.                       
      1. Adjust the potentiometer and for each of the corresponding value of voltage mcasured, measure and record the current in Table 3.
      2. For each measured and recorded values of current and voltage, calculate the power dissipated and fill the values in Table 3. (7 marks)
         Table 3
         

         V(volts)	0.8	1.2	1.8	1.85	1.9	1.95	2.0
         I(mA)
         P(watts)

   3. Plot a graph of current (mA) against voltage (V). (8 marks)
   4. From the graph determine the voltage at which the LED just turns ON. (2 marks)

EXERCISE 5

5. Figure 5 shows the layout of a lighting circuit. Using the materials and tools provided, instal the circuit such that the one way switch operates the lamp.(20 marks)
   

MARKING SCHEME