2017 WAEC GCE Physics Theory Questions & Answers | Physics Practical, Specimen Expo & Apparatus
Physics Theory Questions2017/2018: This is a sample of the examination papers for WAEC GCE Physics Practical Questions & Answers 2017. For those people looking for physics practical neco, OBJ and theory 2017 and waec practical 2017, this post is for you. Please note that this is not an examination expo answer. Use only for study purposes.
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Question 1B
You are provided with two metre rules, two knife edges, optical pin, a known mass and other necessary apparatus.
- (i) Affix the optical pin at the 50 cm mark of one of the metre rules supplied, with a sellotape / plasticine.
- (ii) Place the rule horizontally on the knife edges such that the knife edges are at the 17.5 cm and 82.5 cm marks. Record the distance D between knife edges.
- (iii) Mount the other metre rule vertically with the retort stand and clamp and place it close to the pin to measure the depressions of the metre rule when the weight M is suspended at its mid-point.
- (iv) Read and record the position ho of the pointer on the vertically mounted metre rule, with no weight suspended on the horizontal metre rule.
- (v) Suspend M at the midpoint of the metre rule.
- (vi) Read and record the new position of the pointer hi'
- (vii) Determine the depression of the metre rule H = hj- ho
- (viii) Evaluate log H and log D.
- (ix) Repeat the procedure with the knife edges set at 20.0cm and 80.0 cm, 22.5 cm and 77.5 cm and 25.0 cm and 75.0 cm marks. Each time read and record the distance D and h1
- (x) Evaluate the depressions H in each case and log H and 1og D.
- (xi) Tabulate your readings.
- (xii) Plot a graph with log H on the vertical axis and log D on the horizontal axis.
Observation
Part (a). This question was popular among the candidates and performance was fairly good. Many candidates obtained good readings though for some candidates, it was negative because they disregarded the instruction. Some did not record log H and log D to the required 3 d.p. Graph was simple and well plotted though some candidates still matched points. Precautions were well stated. Part (b) was fairly attempted.
Candidates were expected to:
- Read and record ho to at least 1 d.p in cm
- Read and record four values of D to at least 1 d.p in cm
- Read and record four values of h1 to at least 1 d.p in cm and in trend
Trend:
- as D decreases h1 decreases
- Determined four values of H =| h1 – ho|
- Evaluate four values of log H to at least 3 d.p.
- Evaluated four values of log D to at least 3 d.p.
- List D, h1,H, log H and log D composite table
- Distinguish both axes
- Plot graph using reasonable scales
- Draw line of best fit.
- Evaluate slope
- Avoided parallax error in reading meter rule
- Avoided draught
- Repeated readings shown on table
- Ensured firm clamping of vertical metre rule
- Ensured knife edges are rigid / firm
- Ensured that mass was not oscillating / mass was steady
b(i) Moment of a force about a point is the product of the force and the perpendicular distance of its line of action from the point.
(ii) Using the principle of moments
m(50 – 38) = 60 ( 38 – 16)
12m = 1320
m= 110g
QUESTION 2
Using the diagram above as a guide:
(i) Trace the outline ABC of the equilateral triangular glass prism provided.
(ii) Remove the prism. Draw a line MN such that it makes an angle i = 5° with the normal at N on side AB of the outline.
(iii) Fix two pins at PI and P2 on MN. Replace the prism on its outline.
(iv) Looking through the face BC of the prism, fix one pin at P3 and another at P4 such that they are in a straight line with the images of the pins at PI and P 2'
(v) Remove the prism and the pins. Draw a line to join P4 and P3. Produce line P4P3 to meet the line BC of the outline at Q and line MN produced at P.
Observation
Part (a). This question was not popular among the candidates. Candidates were challenged in making traces as requires. They also exhibited poor knowledge in measuring angles θ, due to poor handling of protractor but they were able to evaluate θ. Some candidates did not attach their traces while some had traces without pin marks indicating that the experiment was not actually performed. However, they were able to plot the graph and determine the slope.
Part (b). This part were not satisfactorily answered by majority of the respondent.
Candidates were expected to
Draw five complete traces showing at least incident ray, emergent ray, from face BC, the normal at N and Q and the intersection of the incident and emergent rays)
Measure and record five values of measured and recorded in degrees and in trend.
Trend: as i increases, e increases.
Measure and record five values of θ to at least 1 d.p in degrees and in trend.
Trend: as i increases, decreases.
- Evaluated five values of = i + e
- List i . in a composite table
- Distinguish both axes
- Plot graph using appropriate scales
- Draw line of best fit
- Evaluate slope and intercept
State any two of the following precautions.
- Ensured pins were vertical / erect
- Sharp pencil/neat traces (seen from traces)
- Reasonable spacing of pins (about 4cm apart)
- Avoided parallax error in reading protractor
- Repeated readings shown on the table
The expected answers for part (b) are:
b(i) Whenever light travels from air to glass, the ratio of the sine of the angle of incidence to
the sine of the angle of refraction is 1.5[2]
OR
Velocity of light in air is 1.5 times greater than the velocity of light in glass.
OR
n = = 1.5
(ii) n = refractive index
n =
OR
C = sin-1 )
= sin-1
= 37.3o
QUESTION 3
Observation
Part (a). This was another popular question among the candidates and satisfactory readings were obtained. The challenges encountered by the candidates were in the plotting of the graph and interpreting it because of the small values got from the evaluation of the reciprocal of I. Precautions are well stated.
Part (b). Most candidates were able to explain the electromotive force of a cell but could not explain how a galvanometer may be adapted to read as an ammeter satisfactorily.
Candidates were expected to:
- Read and record value of Io to at least 1 d.p in Ampere
- Evaluate Value of Io-1 to at least 3 s.f.
- Read and record five values of I to at least 1 d.p in amperes and in trend.
Trend:
- as R increases, I decreases
- Evaluate five values of to at least 3 s.f
- List R, I and in composite table
- Distinguish both axes
- Plot graph using appropriate scales
- Draw line of best fit
- evaluate slope, intercept and k =
State any two of the following precautions:
- Key opened when readings are not being taken
- Ensured clean / tight connections
- Noted/adjusted/corrected zero error of ammeter
- Avoided parallax error on ammeter
- Repeated readings shown on the table
The expected answers for part (b) are:
b(i) The electromotive force of a cell is the work done in driving a unit of electric charge round a complete circuit
OR
- The electromotive force of a cell is the terminal potential difference across a cell when it does not supply electric current to an external resistor.
OR
- The emf of a cell is the total energy per coulomb of charge obtained from a cell
Correct diagram
G = Galvanometer , S = Shunt or low resistor wire
General Comments
The standard of the two papers (Alternatives A and B) compared favourably with those of the previous years in terms of the demands of the syllabus and coverage.
The demands of the questions were well framed and within the experience of the candidates. The language used were simple and comprehensive. The paper tested candidates ability to:
- set-up simple experiment
- carry out the experiments
- collect and analyse data
- plot graphs
- make deductions from the data plotted
- show understanding of the theories behind the experiments.
The rubrics were clear and unambiguous. The marking schemes were comprehensive and adequate. The performance of the candidates was at par with that of the same examination in 2014. The candidates recorded a raw mean score of 24 out of 50 marks and a standard deviation of 09.59 with a candidature of 658393 as against a raw mean score of 24 and a standard deviation of 10.00 in 2014 with a candidature of 665669.
CANDIDATES’ WEAKNESSES AND SUGGESTED REMEDIES
Candidates manifested weaknesses as follows:
- many candidates could not measure and record quantities from metre rule, stop watch and protractor to the required accuracies.
- many candidates failed to express their evaluations from tables such as reciprocals of quantities to the required number of significance (sf) and decimal places (d.p)
- inability to plot graph to the required accuracy.
- inability to make deductions from the graph.
- poor language expression
- poor computational skills.
- obtain correct and neat traces.
- over approximation of data for easy plotting
- candidates disregarded the instruction to start graph from the origin (0,0)
- unable to define centripetal force and explain how galvanometer may be adapted to read as an ammeter.
It was suggested that to remedy these weaknesses:
Teachers should expose candidates to practical activities early enough.
- Qualified and well remunerated physics teachers should be engaged.
- Enough periods should be allotted to physics on schools time table.
- Schools to provide enough and functional apparatus in their laboratory.
- Schools principals should rekindle the reading culture among candidates by creating an enabling environment.
- Previous Chief Examiners Report should be made available to teachers for use rather than keeping the report in their office.
- Schools should sponsors teachers to attend coordination which will help teachers to teach appropriately.