SSC FSFE Physics 2006-ER.pdf

(1)

MINISTRY OF EDUCATION

FIJI SEVENTH FORM EXAMINATION 2006 EXAMINER’S REPORT

PHYSICS

General Comments Paper 1

• The format for 2006 FSF Physics Examination was similar to 2005 FSF Physics Examination.

• The Examination paper tested knowledge and concepts expected to be learned by seventh form Physics students in Fiji.

• The Examination paper was well suited for the range of abilities of students in Fiji as it had both, low order and high order cognitive thinking questions.

• A total of 1353 candidates had registered for this examination. This is an increase of 5.70% compared to the year 2004. However, a significant percentage (4.51%) of candidates who had registered for the examination, did not sit the FSF Physics examination.

• The distribution of the raw marks was approximately normal. It showed a more realistic spread, the paper discriminating well between the able candidates and the weaker candidates.

• During the marking of the scripts, it had 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.

• The setting out of the answers was generally good. Candidates should be advised to list their information clearly, write down the correct formula and show their substitution correctly. Though full marks were not awarded to an incorrect calculation (answer), partial marks were awarded for correct substitution and consistent working.

• Many candidates had poor understanding of the units. It must be noted that S.I Units and

conventions should be used through out the course. Candidates were marked for use of correct unit in one of the questions in Section C. (Question 1, Part (b) (ii) – unit for Electric field)

(2)

2.

NOTE: Overall statistics for Paper 1.

Parameter Score Highest Score Lowest Score Median Range IQR Mean 86 2 29 84 20 32.3

This report is based on statistics from a random sample of 100 raw scores.

SECTION A

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

• In general this section was not very well done. Analysis of scripts show that marks ranged from 2 – 26, with an average of 9, which is 30%.

• A few candidates did not make a choice on some of the multiple-choice questions. They should be encouraged to do so. About 0.15% of the candidates circled more than one alternative as an answer for a few questions. These candidates were penalized and no marks were awarded to questions having more than one possible answer.

(3)

3.

NOTE : Bloom’s Taxonomy was used to design the questions.

(4)

4.

SECTION B

This section contained 10 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 – 26 (out of possible 30), with an average of 12. About 2.66% of candidates did not attempt this section at all. The format of the presentation of the questions were similar to past year examinations and was a good representation of all the 8 topics outlined in the Seventh Form Physics prescription. The following remarks relate to individual questions.

QUESTION 1

This question was very poorly done. It was very discouraging to see that students at Form 7 level lack the understanding of principle of moment and are unable to synthesize the word problems. Marks were awarded for calculating the height, calculating H and P correctly, calculating vertical force V correctly, stating fr = μη and calculation of the coefficient of friction.

QUESTION 2

This question was not well answered by many candidates. Candidate must read and comprehend the question before making any attempts to answer the question.

QUESTION 3

This question was very poorly done. The question as a whole, was very simple, testing candidate understanding of the concepts on SHM. Analysis of scripts showed that candidates had difficulty interpreting the amplitude. The common errors were :

• A = 2 mm

• Conversion of 1 mm to metres

NOTE: In part (b) Amax can be found using the formula : a = A

2

ν

or a = w2A. Due to rounding off in

part (a), v = 3.14 m/s and when substituted in the formula a = A

2

ν

, in part (b), a = 9859.6 m/s².

When using the formula ; a = w²A a = 9869.6 m/s² since the whole value of π was used. This was taken into consideration while marking.

QUESTION 4

This question was also very poorly done. Many candidates lacked the understanding of 2 – dimensional momentum. A few candidates were able to calculate the magnitude of t’s final velocity, however forgot to calculate the direction of t’s final velocity. Candidates could have used horizontal and vertical components of momentum and conservation of momentum to determine the magnitude of t’s final velocity. Students should use their mathematical skills and understanding on Geometry to determine the direction (θ).

(5)

Majority of the candidates used a vector triangle to solve for vt. Generous marks were awarded for drawing the correct vector triangle, stating the conservation of momentum, marking one of the angles as 65° and calculating t = 0.424 kg m/s.

QUESTION 5

This question as a whole was unsatisfactorily answered. Majority of the candidates wrote ‘represents energy level’. Technically this is also correct and marks were awarded.

En = -13.6

n²

principal quantum number energy level

A common preconceived idea is that questions of this nature appear in section C of the examination. The topic “Atomic Spectra” is compulsory and the concepts on this topic can be tested under any section of FSF Physics examination.

QUESTION 6

This question was generally not done well. A few candidates were able to correctly recall the formula E = kQ/r² . However, they were unable to calculate the magnitude of the electric field at x due to all the three charges .

~

Note:

Ex = 1 2

r

kQ ₊

2 2

r kQ ₊

² 3

r kQ

Some candidates were confused in part (b), especially with the words “electric potential.”

Electric potential = V = r kQ

QUESTION 7

This question was fairly answered. A few candidates wrote Vpeak = 240V which is incorrect. Unless explicitly stated, assume all a.c. voltages and current are r.m.s. (root mean square) values. A few candidates did the graphical representation of an alternating voltage as a function of time correctly. However, they did not state the amplitude and period on the graph.

QUESTION 8

(6)

6.

QUESTION 9

This question was very well answered by many candidates. A few candidates left the answer as 1μF for part (a). The effective capitance of the circuit is 3μF. Generous marks were awarded in other parts for correct calculation of charge on the capacitor C1 and C3.

QUESTION 10

(7)

7.

(8)

(9)

(10)

(11)

(12)

(13)

13.

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. The following table presents some statistics on this section.

PARAMETERS RAW SCORES

HIGHEST SCORE LOWEST SCORE RANGE MEAN SCORE 38.5 0 38.5 14

• The table shown below indicates the mean score per question.

Question No. 1 2 3 4 5 6 7

Mean Score 3.2 5.5 6.5 4.3 1.9 3.6 3.0

• This section was fairly done. Many candidates who did not do well in Section A and B, managed to pull through this section. A few candidates were able to pass the overall paper due to their good performance in this section.

• The following remarks relate to individual questions :

SECTION C QUESTION 1

This question was not popular amongst the candidates. For those few candidates who attempted this question achieved marks in part (b) of this question.

Analysis of scripts portrayed the following:

Highest Score : 8.5

Lowest Score : 0

Range 8.5 Mean 3.2 % attempting this

question

(14)

(15)

(16)

16.

QUESTION 2

This question was very popular amongst the candidates. Majority of the candidates attempted this question and were able to achieve good marks (more than 50%) in this questions. Statistics relating to this question are as follows:

Highest Score : 10

Lowest Score : 0

Range 10 Mean 5.5 % attempting this question ~ 90%

Part (a) was well done.

(17)

(18)

(19)

19.

QUESTION 3

This question was a very popular one and was very well answered by majority of the candidates statistics on this question are as follows:

Highest Score : 10

Lowest Score : 0.5

Range 9.5 Mean 6.5 % attempting this

question

~ 95%

(20)

(21)

21.

QUESTION 4

This question was also very popular amongst the candidates. Generally this question was fairly answered. Statistics on this question are as follows:

Highest Score : 10

Lowest Score : 0

Range 0 Mean 4.3 % attempting this

question

83%

Part (a) (i) was generally well done. I would like to stress on the explanation of the concept of

destructive interference – key words like ‘out of phrase’, ‘nodal lines’, ‘cancel out’ must be included in the explanation. Some candidates lacked understanding of thin – film interference.

Part (b) was generally well done, however, (iv) was poorly done.

dt dy

= V

Part (c) was fairly done. Some candidates had difficulty in the calculation of the cross – sectional area of the wire fence (i) and (ii) answers were affected.

Acircle = πr2 = 4

2 d

π

(22)

(23)

(24)

24.

QUESTION 5

This was not favoured by the candidates. Those who attempted this question generally did not do well. Statistics on this question are as follows:

Highest Score : 6

Lowest Score : 0

question

1.1%

(25)

(26)

(27)

27.

QUESTION 6

This question was fairly answered by the candidates. The following statistics relate to this question.

Highest Score : 7

Lowest Score : 0

question

~50%

Part (a) of this question was quite well done, however most of the candidates forgot to state the direction of magnetic field. Most of the candidates found T instead of t.

Part (b) was generally well done.

(28)

(29)

(30)

30.

QUESTION 7

This question was quite popular amongst candidates and was fairly done.

The statistics on this question are as follows:

Highest Score : 7

Lowest Score : 0

question

~50%

Part (a) of this question was well answered by many candidates, however, most candidates left the answer as 100π rad/s in (ii). The angular velocity of the coil 2πf which is equal to 200π ² rad/s.

Many candidates are familiar with peak voltage generated by the coil.

(31)

(32)

32.

PAPER II GENERAL COMMENTS

• The format for 2006 FSF Physics Examination – Paper II was very similar to the 2003 paper. • It tested the practical work outlined in the Seventh Form Physics course.

• The marks obtained in Paper II are low. This portrays a low level of performance in practical work in Seventh Form Physics and the manner of answering question in this years’ Paper II seems to confirm that practical components are not adequately covered in school laboratory classes.

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

• Given below is the statistics for this years’ paper II

Parameter Score

Highest Score : 37

Lowest Score : 0

Range 37 Median 19 IQR 11 Mean 21.2

Note: All the statistics are based on raw score.

The following table shows the mean score per question.

Question No. 1 2 3 4 5 6 7 8

Mean Score 2.0 1.5 1.5 3 2 2.3 2.5 1.8

(33)

33.

QUESTION 1

(a) (i) Generally not well done. (ii) Satisfactorily answered.

(iii) Many candidates drew the straight line beginning from the origin but did not label the axes.

(b) Many candidates were able to work out the correct percentage uncertainty however had difficulty in calculating absolute uncertainty. Rounding off was a problem.

QUESTION 2

(a) Well done.

(b) Many candidates had difficulty in drawing the new preferred symbol for wires joined and voltage divider.

(c) Very poorly done. A few candidates had swapped the value of k and n. Many had calculated slope incorrectly.

QUESTION 3

Generally not well done. Many candidates had (i) and (ii) wrong. A few candidates did not know the unit for angular acceleration.

QUESTION 4

(a) Generally well done.

Common error : Failure to equate sum of potential in a closed path to zero.

(b) Very poorly done. The procedure was not correctly described.

QUESTION 5

(a) Satisfactorily answered. However, a few candidates actually drew the equipment as it looks in reality. Technically, marks were awarded to these candidates as the question did not specify “circuit” diagram.

(34)

34.

QUESTION 6

Parts (i) and (ii) were generally well done. Parts (iii) and (iv) were poorly done. Candidates must read the question thoroughly. For (iii) candidates must state the relationship between R and L in the form of an equation. (iv) ρ = slope x A

Unit for ρ is Ωm

QUESTION 7

Generally well done. Most candidates answered (i) – (iv) correctly. However, they had difficulty in parts (v) and (vi).

QUESTION 8

Very poorly done. Majority of the candidates could not analyse the waveform shown on the oscilloscope. A few candidates had calculated Vpeak-to-peak.