Physics Paper 3 WASSCE (SC), 2017

Alternative B

 

 

 

Question 3B

 


Observation

 

           
Part (a) This was a popular question among the candidates. Many candidates attempted the question and performed well.
(b) Candidates response was fair.
Candidates were expected to:

  • measure and record the value of XY to at least 1 d.p in cm.
  • read and record the values of Io to at least 1 d.p in A
  • read and record the values of Vo to at least 3 d.p in volt
  • record six values of R in ohms
  • read and record six values of I to at least 1 d.p. in A and in trend
  • read and record six values of V to at least 1 d.p. in V and in trend
  • show composite table containing at least R, V and I          
  • Both axes correctly distinguished   
  • plot a graph using reasonable scales
  • draw line of best fit
  • determine the slope of the graph
  • state any two of the following precautions.

e.g.

  • Ensured clean terminals.
  • Ensured tight connections.
  • Key removed when readings were not taken 
  • Avoided error of parallax when reading ammeter/voltmeter
  • Noted/Avoided zero error when reading ammeter/voltmeter
  • Repeated readings shown on table.

b(i)      Ohm’s law                                                                                                 

Provided the temperature is constant, the current passing through a metallic conductor (wire) is directly proportional to the potential difference across its ends