ELECTRICITY PAPER 2 - 2019 LAINAKU JOINT MOCK EVALUATION EXAMINATION

EXERCISE 1

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

1. Connect the circuit as shown in Figure 1. Let the examiner check your work (7 marks)
   
2. Figure 1
3. Vary the base resistance R_B to obtain each of the base current I_B values shown in table 1. For each value of I_B, measure and record in the table the corresponding values of V_CE and I_C.
   Table 1
   

   IB(µA)	VCE(V)	IC(mA)
   200
   220
   240
   260
   280
   300

4. 1. Determine the current gain β when I_B=240µA (2 marks)
   2. Plot a graph of I_C against V_CE (5 marks)Using the values in table 1:

EXERCISE 2

Using the tools and equipment provided, make the model of a fluorescent lamp rain guard as shown in Figure 2

EXERCISE 3

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

1. Connect the circuit shown in Figure 3 and let the examiner check your work (6 marks)
   

2. Close the switch. Adjust the potentiometer to obtain voltage reading shown in Table 2. For each voltage reading obtained, measure and record the corresponding current values. (5 marks)
   Table 2
   

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

Plot a graph of current against voltage                                                 (6 marks)

1. From the graph:
2. Determine the resistance when the voltage is 1.3V
3. Give a reason for the shape of the graph (3 marks)

EXERCISE 4
Using the pre-fabricated circuit provided in Figure 4, perform the following tasks:

1. With the switch open:
   1. Connect Voltmeter between A and B (Observe polarity)
   2. Connect Voltmeter between C and D (Observe polarity) (2 marks)
      (Let the examiner check your work)
2. Close the switch. Adjust input voltage and complete the table below (10 marks)
   Table 3
   

   Input Voltage Vin (V)	0	1.0	2.0	3.0	4.0	5.0	6.0	7.0	8.0	9.0	10.0
   Output voltage Vz (V)

Plot the graph of Vz against Vin (5 marks)

EXERCISE 5

Using PVC sheathed wiring, complete the installation shown in Figure 5, such that the bell is operated from either A or B   (20 marks)

MARKING SCHEME

EXERCISE 1

EXERCISE 2

EXERCISE 3

EXERCISE 4

EXERCISE 5