waecE-LEARNING
Home
Technical
Mathematics
Languages
Science
Social Science
Art
Literature Arabic Islamic Studies C.R.K History MusicVisual Art Clothing/Textile Home Management Shorthand
 
Physics Paper 2, Nov/Dec. 2013  
Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Main
General Comments
Weakness/Remedies
Strength
















Question 8

   Question 8
   Explain ‘threshold frequency’ with respect to photoemission.
    This is not a popular question among the candidates.  Most candidates missed   out the key words like minimum frequency; appropriate frequency.  Hence they could not score.

_____________________________________________________________________________________________________
comments

Some candidates in response described photoelectric emission only.  Such candidates should have gone further to define/explain threshold frequency.  Performance was poor.
        
     The expected answer is
             When radiation of appropriate frequency falls on a metal surface, electrons are ejected  from the surface.  The minimum frequency of a radiation that must be incident on  the metal surface to liberate/set free electrons from the surface is the threshold frequency.

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