SSC FSFE Physics 2007-ER.pdf

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MINISTRY OF EDUCATION

FIJI SEVENTH FORM EXAMINATION

2007

PHYSICS

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General Comments Paper 1

• The format for 2007 Fiji Seventh Form Physics Examination paper is similar to past year papers. The format of the paper has been unchanged since 1989.

• The examination paper on the whole had tested knowledge and concepts expected to be learned by seventh form Physics students particularly :

- familiarity with basic concepts, principles and theories of physics - problem solving techniques

- Using mathematics as a language to describe relationship between physical quantities - knowledge of practical situations encountered during practical lessons and its applications ;

and

- coverage of the Fiji Seventh Form Physics prescription. The prescription includes an extension of all major topics in the Fiji School Leaving Certificate Examination Physics.

• A total of 1404 candidates had registered for this examination. There was an increase by 2 % in the number of candidates registered for this examination compared to the year 2006.

• In the duration of the making of the scripts, it has been revealed that some candidates did not follow instructions given on the paper. All the instructions were very clearly stated on page 1 of the Question paper and Answer Book. Individual sections and questions had instructions which candidates had to follow.

- a few candidates used pencil and red ink for writing answers.

- Section A and B were compulsory. Candidates should have noted the choices in Section C of the paper. Some candidates answered all the seven questions in Section C.

• A number of students had difficulty with the setting out of the answers. Although most of the students managed to list down the known and the unknown quantities with the formulas and the substitution, they were not placed in an organized manner. Markers had to look around for the working and the answers. Teachers are required to emphasise the importance of clearly laying

out the steps involved in the calculation and the final answer. The next part should be clearly separated from the previous one by at least leaving a line. Candidates should be well advised to list the information clearly, write down the correct formula, show the conversion of parameters in S.I. unit and show the substitution correctly. Though full marks are not awarded to an incorrect calculation (answer), partial marks are awarded for correct substitution and consistent working.

• Mathematical errors, especially those dealing with algebraic fraction, and powers of 10 were quite common.

e.g

C

1 =

F

μ 3 1 ₊

F

μ 3 1

C

1 =

F

μ

3 2

C =

uF

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It seems that basic mathematical skills and concepts are not fully grasped by most candidates. It is imperative that teachers should revise and recapitulate the basic mathematical concepts in the classroom.

• Candidates should be reminded and made aware of the two decimal point rule. Students were not penalized for this during the marking. All rounding off should only be done at the final step and

not at the intermediate steps, as this would greatly affect the final answer.

• Some of the candidates were unable to complete the examination in the stipulated time. This is either due to poor time management or failure to comprehend the questions. Teachers need to train their students in the classroom to complete a question on time.

• The conversion of values to the right unit was a major problem in many questions. It should also be noted that the constants given on page 3 of the answer book should be used and not other accepted values.

• Finally, I wish to call upon the teachers to encourage and motivate their students during the teaching and learning of Physics. Teachers should endeavour to maintain link between physical ideas and relevance to student’s lives in their teaching by making reference to real life experiences and relevance of the concepts to real life.

The marking scheme will accompany so answers are not included in this report.

NOTE: Overall statistics for Paper 1.

Parameter Score Highest score Lowest score Median Range IQR Mean 91 9 41 82 29 43.5

This report is based on statistics from a random sample of raw scores. The distribution of the raw

scores was approximately normal. It showed a more realistic spread, the paper discriminating very well between the able and less able candidates.

SECTION A

• This section contained 30 multiple-choice questions, each worth 1 mark.

• This section was compulsory and candidates should have spent approximately 54 minutes in this section.

• In general this section was not very well done. Analysis of scripts showed that marks ranged from 4 – 26, with an average of 14.

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• While some questions in this section were challenging for the very able students, there were enough questions in the examination paper to enable weaker candidates to score marks. The designing of questions had taken into account of Blooms Taxonomy low-order and higher – order thinking.

The table below gives the percentage of the choices attempted by the students. The choice with an asterisk (*) are the accepted answers.

Q. # A B C D Comment

1 12 50 * 30 * 8 The accepted answer was B. Due to wrong rounding off A was also accepted as the answer. Question well done.

2 20 *

40 30 10

Fairly done. Student were tested the understanding of satellite motion in this question.

3 50 18 *

28 4 Poorly done. Students lacked the understanding of lift principle

4 20 8 16 * 56

Generally well done. Candidates understood the concept of centre of mass

5 8 16

*

54 22

Well done. Students showed good understanding of Newton’s Law of Universal Gravitation and Tension.

6

*

60 10 16 14

Well done. Students showed good understanding of air resistance in projectile motion.

7. 15 19 *

44 22

Fairly done. Some students lacked the mathematical aspects of this question.

8. 24 24 45 * 7 Fairly answered. Some students lacked the understanding of rotational motion.

9. 42 *

37 13 8

Poorly done. The students lacked the basic knowledge of vertical circle.

10. 17 *

50 16 17

Well done. Students had good knowledge of the theory on electromagnetic spectrum.

11. 16 20 13 * 51

Well done. Question on Doppler effect.

12. 15 *

19 59 16

Very poorly done. Students lacked the understanding of rotational inertia and how the object will roll down a slope.

13.

*

25 23 32 20

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14. 30 *

43 9 18 Well done. Relation between tension and vibration of a string.

15. 8 11 50 31 * Average performance. Students were not able to differentiate the between the waves traveling in opposite direction.

16. 19 1

*

79 1

Excellent performance. Students understood the calculation on Wheatstone bridge.

17.

*

35 26 8 31

Average performance. Many students lack the understanding of the air wedge.

18 20 32 19 * 29

Poorly done. Students lack the understanding of the application problems.

19. 20 43 * 9 28 Well done. Coulombs law well understood

20. 13 14 60 * 13 Very well done. Calculations based on capacitors well understood.

21. 8

*

60 14 18

Very well done. Back emf concept well understood by the students.

22. 23 28 *

38 11

Average performance. Many students lacked the theoretical aspect of Bohr model.

23. 10 * 30 34 26 Very poorly done. Students lacked the definition of Faradays Law.

24

*

62 19 10 9

Well done. Conversion of a galvanometer into an ammeter well understood by the students.

25. 23 27 8

* 42

Well done. Theories of LCR circuit well understood.

26.

*

38 19 23 20

Average performance. Many students lack the calculation on addition of capacitors in series and parallel.

27.

*

75 9 12 4

Excellent performance. Students managed to get the unit for magnetic field.

28.

*

34 29 22 15

Average performance. Many students lack the knowledge of electric potential energy.

29. 23 22 * 32 23 Poorly done. This was an application question.

30. 17 *

26 39 18

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SECTION B

• This section contained ten questions and all were compulsory. Each question was worth 3 marks.

• Analysis shows that this section was difficult to most candidates. The marks ranged from 0 – 28 (out of a possible 30), with an average of around 12.

• A handful of candidates did not attempt this section at all and as a result, they lowered the mean score of this section.

• The following remarks relate to individual questions. The detailed marking scheme is attached so answers are not given with the comments

QUESTION 1

Many students were able to determine the individual forces ie. FR (frictional force), FS (sliding force) and

FN (normal force) however, they had difficulty determining the net force to calculate the acceleration and

the tension.

Marks were awarded for writing the correct expressions calculation of each of the forces and the acceleration and tension.

Consistency was applied to part (b).

QUESTION 2

This question was well answered by many students. Few students were not able to relate the concept of

r v

=

ω . The concept of loss in potential energy is equal to gain in kinetic energy was very well illustrated.

QUESTION 3

Very few students were able to answer the actual question ie. calculate the angular displacement which was supposed to be in radians. Many students were able to calculate the angle in degree which carried 2 ½ marks. Some students were also not able to do the right conversion of the units. Some students also used the formula for the dark band.

QUESTION 4

This question was poorly done by many students. A common mistake was the use of the wrong formula ie. ₂

r kq E = or

r Gm g =

A number of students also were not able to realize that the gravitational filed is a vector quantity and tried to add the two values calculated linearly.

Some students also use the concept of centre of mass and momentum to do this calculation.

QUESTION 5

This question involved the Doppler Effect where both the source and the observer were moving. Only motion of one was supposed to be tested. Students were awarded full mark in part (a) for calculating the wavelength only. Students were awarded grace mark for part (b).

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QUESTION 6

Many students did not manage to get the part (a) correct. However students were awarded ½ mark for the one of the correct formulas. Many students managed to get this mark. Part (b) and (c) was well done by many students.

Majority students got the formula correct even if they did not get the final answer.

QUESTION 7

Part (a) for this question was very well done. Many students were able to get the answer correct here. For part (b) many students were not able to reproduce the correct formulas ie. 2

2 1

CV

E = or E QV

2 1 = .

Consistency was applied in this question from part (a).

For part (c) many students wrote potential energy when it was supposed to be electrical potential energy.

QUESTION 8

Part (a) was fairly done. Recall of formula was a major problem in this question. A number of students lost mark since they were not able to state the correct formula. Some students also lost mark for not converting cm to m for length in the problem.

Part (b) was very poorly done. Most of the students were not aware that the magnetic field at the end is halved. Consistency was applied to this part of the question.

QUESTION 9

Part (a) was fairly done. However many students seemed to have forgotten about the Rutherford Experiment. Students were talking about electrons or atoms instead of alpha particles.

Part (b) was very poorly done. Only few students managed to get this correct.

Part (c) was fairly done however many students seemed to lack the concept of “energy is quantized”.

QUESTION 10

Average performance in part (a). Many students were not able to state the formula correctly and hence did not get the right answer.

For part (b) many students were able to get the shape correct but were not able to plot the 0.02 second as the time for one cycle.

Part (c) was fairly done. Many students were able to recall the formula P = VI and get the answer.

SECTION C

• This section of the paper contained seven questions, out of which, any four questions were to be answered. Each question was worth 10 marks.

• Candidates should have spent approximately 72 minutes in this section.

• This section was fairly done. A very many candidates who did not go well in sections A and B, managed to pull through this section.

• Approximately 1 % of the candidates did not attempt any of the questions in this section. This statistics portrays the following :

- inability to complete the examination at the stipulated time due to poor time management or failure to comprehend the questions.

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• It was also noted that some students lost marks due to wrong choice of questions. Teachers should emphasise that the questions to be attempted should be decided during the reading time ( first ten minutes of the examination )

• A few of the candidates tried to communicate to the examiners/markers by writing small notes in this section. Candidates need to be well informed that any means of communication to the examiner/marker, will dealt with seriously and disciplinary actions will be taken against these candidates.

• The following table presents some statistics on this section :

PARAMETERS RAW SCORES HIGHEST SCORE LOWEST SCORE RANGE MEAN SCORE 38 0 38 16.8

QUESTION 1

This question was very popular and generally very well answered by majority of the candidates. Analysis of scripts portrayed the following :

Highest score : 10

Lowest score : 0

Range : 10

Mean score : 7

% attempting this question : 95

Part (a) was very well answered except for few students who lacked the basic physics knowledge. Consistency was applied throughout this part and due to this many student still got high marks although they got the first or second part incorrect.

Part (b) was generally well done however the following mistakes were noted - difficulty in working out the area.

- Students did not convert the radius to metre.

There was average performance from part (c). Some students did not get the formula correct for this part.

QUESTION 2

This question was another popular and was generally well answered by a number of candidates. Analysis of scripts portrayed the following :

Highest score : 10

Lowest score : 0

Range : 10

Mean score : 5.5

For part (a), (i) and (ii) was not well done. Students were not able to get the value of impulse correct. Many were also not able to see that for (ii) the magnitude will remain same but only the direction will change.

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For part (c), (i) was very well done. Students were able to get the right formula and correct substitution to get the answer. (ii) was poorly done. Students were unable to relate radius and magnetic field. They also lacked the mathematical knowledge.

QUESTION 3

Average number of students attempted this question. There was average performance noted. Analysis of scripts portrayed the following :

Highest score : 10

Lowest score : 0

Range : 10

Mean score : 6

For part (a), (i) was poorly done. Only about 20% of the students had the correct answers. Many students were able to see that a magnetic field is involved however only few were able to realize the condition for the conductor to be suspended in the position shown. Some left the question unanswered. For (ii) the direction of the current shown in the diagram was opposite to the actual direction. So both directions ie. from P to Q or from Q to P were accepted. Many students managed to get the mark for this part.

Part (b) was generally well done. Common mistake was the incorrect use of the unit. This was due to students not reading the question carefully.

Part (c) was well done however some common errors noted were - unable to recall the correct formula

- missing out the negative sign as the wheel was slowing down

QUESTION 4

This was one of the most unpopular questions. Less than five percent of the students attempted this question. It was difficult to have the good analysis due to few scripts available. This question was mostly chosen by low scoring candidates and was not done well.

Analysis of scripts portrayed the following :

Highest score : 8

Lowest score : 0

Range : 8

Mean score : 3.5

% attempting this question : < 5

Part (a) was not well done. It was evident that students have not learnt to relate SHM to circular motion and have memorized the formula for SHM in problem solving. More time need to be spent on reference circle in the class.

Many students left (iii) unanswered. Mathematical knowledge was needed here where students were to differentiate the equation obtained in (ii) to get the expression for the acceleration. Poorly done.

Part (b) was generally well done by the students who attempted. A common mistake in this part was that students did not know that organ pipe had closed end. This should be strongly emphasized in class. Part (c) was poorly done. Average number of students got (i) correct. Majority students who attempted had incorrect manipulation for (ii).

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QUESTION 5

This was another popular question. About 90% of the students attempted this question. Most of the students managed to get above 50% in this question.

Analysis of scripts portrayed the following :

Highest score : 10

Lowest score : 0

Range : 10

Mean score : 6.5

Part (a), (i) was done very well. Majority of the students were able to get this expression correct.

For (ii), many students lost mark for having wrong sign ie. “+” and “-“ for both the loops. Hence incorrect values for I1, I2 and I3 were obtained in part (iii). Since marks were divided for the question right from the

top many students did manage to get above 2 marks in this question.

Part (b) was not well done, however consistency was applied to (iii) where many students were able to get the one mark. Average number of students got this correct for (i) and (ii).

Part (c) was very well answered. Majority of the students who attempted this question got it correct. Few students were not able to recall the correct formula where they lost marks.

QUESTION 6

Highest score : 10

Lowest score : 0

Range : 10

Mean score : 5.5

% attempting this question : 55%

Part (a) was well answered. However some students had difficulty with the phasor diagram.

Common answers for (iv) were radio, electrical appliances and TV. There should be more emphasis on how and for what the circuit is used in these appliances.

Although part (b) was direct formula application it was not well done. Many students failed to chose the correct formulas for this part. Responses also indicated that students were not able to understand the concepts involved (i) and (ii). (iii) was well answered.

Part (c) was well answered by those who attempted this question. A common error in this part was the inability of the students to recall the correct formulas.

QUESTION 7

Highest score : 10

Lowest score : 0

Range : 10

Mean score : 6

Part (a) showed average performance by the students who attempted. Common errors identified in this part were

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- forgetting to incorporate number of turns (N) in the formulas Consistency was applied in this part.

Part (b) was not well done. Many students did not seen to have a good understanding of the concepts involved in LR circuits as well as recall of the formulas. There need to be more emphasis on this aspect in the class.

Part (c) was generally well done. Some students were not able to get the correct series in (i). Few students had difficulty recalling the correct formula in (iii)

PAPER II

GENERAL COMMENTS

• This paper tested the practicals outlined in the seventh form Physics course by the curriculum development unit of Fiji.

• The aims and objectives outlined in the Physics prescription and explanatory notes, associated with the required practical programme should be an integral part of the teaching programme and practical work and not to be taken in isolation. The experiments should give the pupils first hand experience of the ideas, and in many cases introduce the ideas to pupils before the theory teaching begins.

•

• Generally the marks obtained in Paper II were not encouraging although majority questions were not high level. The quality of answers written in the examination is disappointing. This portrays a low level of performances of practical work in seventh form Physics and the manner of answering questions in this years Paper II seems to confirm that practical components are inadequately covered in school laboratory classes in many schools.

Teachers need to note that since not many high level questions are asked in this section, the average and below average scoring students can do much better in this section. Teachers need to develop the skills of scientific inquiry in our candidates so that they are able to acquire the skills and apply in unfamiliar situations.

• Candidates scored well on questions that relate more to theoretical in nature rather than the practical aspects of Paper II.

• Given below is the statistics for this year’s Paper II.

PARAMETER RAW SCORE

Highest Score Lowest Score Median Range IQR Mean 37 0 17 37 9 14

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Question 1

Generally average performance seen. Any one error in (a) was accepted.

For (b), (ii) many students failed to get the final unit ie. kgm2. (iii) to (v) was not well done. Students mixed the kinetic and the potential energy. Many were also not able to identify the missing energy in (v).

Question 2

Part (a) and (b) had an average performance. Teachers need to emphasize more on what instruments that need to do different measurements.

Part (c) was very poorly done. Less than 10% of the students managed to get full mark in this section. The students totally missed the concept that was tested in this question. Many students were trying to time the unwinding of the yoyo to find g which is not discussed in any part of the lab work. Teachers need to emphasise that practical work is not confined to the laboratory only. Students also need to read the question carefully.

Question 3

Majority students managed to pass this question due to part (a) and (d) Part (a) was well done.

For part (b) many students were not able to get the correct answer here. A common reponce was to make “ ……so that the current could flow easily” which does not relate to the concept.

For part (c) the teachers should emphasise that the variable resistor is used to vary the voltage/current is not enough. Students need to give the actual use in the type of situation involved.

Question 4

Part (a) had average performance. Many students were not able to get the 1½ cycle correct. For part (b) some students were not able to get the correct formula.

Due to consistency many students were able to get part (c) correct.

There was an average performance in part (d). Common errors were not recalling the formula not having the values in the right unit.

Part (e) was poorly done. Only few students were able to identify that tension need to be increased to increase the distance between the nodes.

Question 5

This question was generally well done.

Part (a) was well done however some students were not able to identify that the dry cell was connected wrongly.

Part (b) was very well done except for few students who missed out on the term elastic potential energy. They just wrote potential energy which is not enough for this concept.

Question 6

Part (i) was very well done since the panel accepted the answer show deflection only. However, teachers need to discuss the complete process involved ie. show defection initially and then gradually come to zero.

Few students were able to get part (ii) correct. Many students were not able to see that a 4 MΩ resistor is big.

Generally average performance seen in part (iii). Any related term that was able to make the statement correct was accepted.

Part (iv) was very poorly done. Majority students completely lack the reason as to why a time constant is used.

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Question 7

Part (i) was very poorly done. Many students had no knowledge of how a pendulum is used as a SHM. Part (ii) was well done.

Average performance seen in part (iii). Teachers should discuss the reasons for obtaining the graph. Part (iv) was a direct mathematics application. Many students showed poor mathematical knowledge here. Part (v) was part of the analysis of the graph to get the period. Many students were not able to identify the position of the slope in the expression.

Question 8

Average performance in part (a).

Many students lacked the relation between the change in voltage and the thickness of the wire. Students also lacked the understanding of the relation between the thickness of the wire and heat dissipation. Poor performance in part (b).

Any two variables listed were given full mark in part (i)

Many students were not able to state how the analysis will be done and also the conclusion that could be drawn.

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