UNIVERSITY EXAMINATIONS: 2016/2017
EXAMINATION FOR THE CERTIFICATE IN INFORMATION
TECHNOLOGY
CIT102 FOUNDATION PHYSICS AND ELECTRICITY FOR IT
DATE: AUGUST, 2017 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One & ANY OTHER TWO questions.
QUESTION ONE [30 MARKS] – COMPULSORY
a) Define the following terms 9Marks
i. current
ii. work
iii. voltage
iv. force
v. frequency
vi. wavelength
vii. acceleration
viii. resistance
ix. kinetic energy
b) State the following laws and principles 6Marks
i. Ohm’s Law
ii. Newton’s second law of motion
iii. The principle of conservation of energy
c) A 26Kg rock falls off a cliff onto the beach 20m below. Calculate 5Marks
i. the speed at which it hits the ground
ii. the deaceleration if it buries itself 33cm into the soft sand
d) Calculate the current needed by a 120W computer connected to a 240V source.
e) Find the wavelength of wifi signal transmitted at 2.5GHz 2Marks
f) Give the use of the following instruments needed by an IT technician; 3Marks
i. multimeter
ii. ohmeter
iii. voltmeter
g) Give the units of measure for each of the following quantities 5Marks
i. Mass
ii. Charge
iii. Current
iv. Work
v. Energy
QUESTION TWO [20 MARKS]
a) Define the terms 5Marks
i. free electrons
ii. charge
iii. electric potential
iv. conductor
v. insulator
b) Using atomic theory explain what an electric current is. Draw relevant diagrams. 6Marks
c) Explain the difference between series and parallel circuits. Draw circuit diagrams also. 4Marks
d) Explain why the computer technician connects all computers in parallel to the power supply
2Marks
e) Explain what a short circuit is and how a technician can troubleshoot such a fault 3Marks
QUESTION THREE [20 MARKS]
a) List four types of motion 4Marks
b) A ball is kicked horizontally over a cliff into the sea at an initial velocity of 12m/s. Calculate;
7Marks
i. the velocity of the ball when it hits the water surface
ii. the displacement from the foot of the clif to the ball when it hits the water
c) Find the displacement of a 10Kg mass pushed with a constant force of 7N over a frictionless
surface for 12.8s 3Marks
d) A ball kicked vertically up from the to a height of 3.7m. Calculate;
6Marks
i. The balls velocity when it lands
ii. The time the ball takes in the air
QUESTION FOUR [20 MARKS]
a) Define the following terms as used with regard to light 3Marks
i. reflection
ii. refraction
b) Briefly explain how the principle of refraction is used to make the optical fibre cable 3Marks
c) A series circuit has three resistor s of 30Ω, 40Ω and 20Ω. Draw the circuit 5Marks
i. calculate the total resistance
ii. calculate total resistance if the resistors are connected in parallel
d) A technician suspects that a network cable has an open circuit fault. Explain how the ohmeter
can be used to do the measurement 4Marks
e) List examples of two conductors and two insulators 2Marks
f) Briefly describe electromagnetic waves. Hence explain how radiowaves are used in
communication in computer networks 3Marks
QUESTION FIVE [20 MARKS]
a) Define the following terms. 2Marks
i. charge
ii. electric potential
b) Describe three parts that make an electric circuit. Draw a circuit. 4Marks
c) Give the difference between ac and dc current 2Marks
d) Give symbols for the following electronic devices; connected wires, bulb, resistor, capacitor
2Marks
e) Give the difference between transverse and longitudinal waves. Give examples of each 3Marks
f)
i. Explain the terms reflection and refraction.
ii. Explain how refraction is used in the optical fiber 4Marks
g) Find the net force if three forces act on an object. 20N at 37o
, 30N at 145o
, and 41N at 227o
Sketch the forces. 3Marks
