# 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

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

EXERCISE 3

1. 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

1. Figure 4 shows a block diagram of the electronics circuit board provided
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

1. 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

 1C Reasons for differences- For parallel circuits -Voltage across the circuit is same -Total supply current I = I₁ + I₂- Total resistance:R =   1   +   1           R₁     R₂ For series circuit-Total supply current is same -Total supply voltage V = V₁ +V₂-Total resistance R = R₁ + R₂ 3C Tests carried out-Insulation resistance test at the plug -Polarity and continuity test for the cable 4C Graph-Axes - 2 x 1 = 2-Plotting - 7 x ½=3½-Current -1½ d Determining voltage when LED is ON - 2 x 1 = 2 marks

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