Electricity Paper 2 Questions and Answers - MECS Pre Mock Exams 2023

Instructions To Candidates

1. There are FOUR exercises in this paper
2. Candidates are allowed 30 minutes for each exercise
3. Each exercise will be awarded a maximum of 20 marks
4. Do NOT do work related to other stations while at a different station
5. Attempt All the exercises as directed by the examiner(s)

For Examiner’s Use Only

QUESTIONS

EXERCISE 1 (20mks)

1. Pictorial view
   
2. Development 
   

EXERCISE 2: (20mks)

The figure below shows the isometric view of a metal bracket. Study the drawing carefully. The bold arrow indicates the front view of the bracket.

On the plain paper provided, draw the following third angle orthographic views of the guide:

1. The Front elevation
2. The End elevation
3. The Plan view

Label the views and indicate six main dimensions on the drawing 

EXERCISE 3: (20mks)
The figure below shows a Zener diode testing circuit

Use the equipment and components provided to carry out the following tasks:

1. With the power OFF, set up the circuit as shown in the figure above. Let the examiner check your circuit before proceeding (5mks)
2. Put ON the power and set the supply voltage, Vs to various values as shown in the table below. Record the corresponding values of the current through the diode, ID and the voltage across the diode, VD (8mks)
   

   Vs (v)	ID (mA)	VD (v)
   2
   4
   6
   8
   10
   12

3. Reduce the supply voltage to zero and turn OFF the power supply
4. Draw a graph of ID against VD on the graph paper provided please turn over(PTO) (4mks)
5. From the graph, determine the voltage at which the Zener diode starts conducting significantly (1mk)
   V_Z = --------------------------------------------------------------------
6. Give a practical application of the circuit tested above (2mks)
    

EXERCISE 4: (20mks)

The figure below shows the layout diagram of a lamp circuit carried out in p.v.c. insulated and sheathed cables.

1. Install and wire the circuit such that the lamp is controlled by the one-way switch (17mks)
2. Name three types of tools and three types of accessories used in the exercise (3mks)
   Tools:
   
   Accessories:

SCORE SHEET

Exercise 1: Metal - Work

Exercise 3: Diode Testing Circuit

Exercise 4: Installation

MARKING SCHEME

Exercise 2 

1. The Front elevation
2. The End elevation
3. The Plan view
   Label the views and indicate six main dimensions on the drawing
   • Solution-3mks
   • borderline-2mks
   • Dimensioning-4mks
   • Accuracy-3 mks
   • neatness-2 mks
   • Outline-3mks
   • labeling- 3mks

Exercise 3

1. Install and wire the circuit such that the lamp is controlled by the one-way switch (17mks) 
2. Name three types of tools and three types of accessories used in the exercise (3mks)
   1. Hammer
   2. Screw driver
   3. side cutter
3. Accessories: 
   1. switch
   2. lamp holder
   3. pattress box
   4. junction box