Applied Electricity Paper 2 , Nov/Dec. 2012
 Questions: 1 2 3 4 5 6 Main
General Comments
Weakness/Remedies
Strength

Question 1

 (a) Define the following with respect to alternating current:            (i)        impedance;            (ii)       reactance.                                                 '3.14Q.Q.          31 S· s.n. son. r __ ..-J(OO)---1 f--r-=_::J--i---'                                                        XL                   Xc                    R .I II'                 L-- ___________________ ~ rv'\.- __________ -J ioov, 50Hz Fig. 3 (b) In Fig. 3, calculate the:            (i)        impedance;            (ii)       current, 1.

_____________________________________________________________________________________________________
Observation

The expected answers were:
(a)(i)        Impedance is the total opposition afforded by an electric circuit to
the passage of alternating current.
(ii)     Reactance is the opposition afforded by a pure inductor or pure
capacitor to the passage of alternating current.
(b)(i) Impedance, Z = .JR2 + (XL - XC)2
= .J502 + (3.14 - 318.5)2
Impedance, Z = 319.3 Q
(ii)      Current, I = ¥
100
=--
319.29
Current, I = 0.313 A
306

The question was on Alternating Current Circuit Theory. It was well
attempted by candidates. The candidates' performance was reported to be
good.

 Powered by Sidmach Technologies(Nigeria) Limited . Copyright © 2015 The West African Examinations Council. All rights reserved.