SPM essay questions in chapter 6.

2. Puncak bertindak sebagai kanta cembung
The crest acts as convex lens
Puncak menumpukan sinar cahaya untuk menghasilkan garis cerah
The crest converge the light rays to form the bright line.
Lembangan bertindak sebagai kanta cekung
The trough acts as concave lens
Lembangan mencapah sinar cahaya untuk membentuk garis gelap.
The trough diverge the light rays to form the dark line.

3. Panjang gelombang sebelum dan selepas
melalui celah adalah sama.
The wavelength does not change before
and after passing through the gap
Sebelum melalui celah, muka gelombang
lurus
Before the gaps, the wave fronts are
straight
Muka gelombang bengkok bila melalui celah.
The wave fronts bend when passed through the gaps
Muka gelombang membulat apabila melalui celah kecil.
The wave front is circular when the gap is smaller.
Pembelauan lebih jelas apabila saiz celah kecil.
Diffraction is more obvious when the size of the
gap is small.

5. • Build a slanting barrier
• Reduce speed / energy of the wave
when the depth of water decreases
• The surface of the barrier is made
rough / porous / uneven
• To reduce reflection of the wave
• Build the new jetty at the bay
• Water is calm in the bay.
• Water is spread according to the
shape of the bay
• Build a barrier with small opening
surround the bay.
• Diffraction happens at the opening
so can spread the energy or reduce
amplitude of the wave
• Bina benteng bercerun
• Mengurangkan laju / tenaga gelombang
apabila kedalaman air berkurang
• Permukaan benteng kasar / poros /
tidak rata
• Untuk mengurangkan kesan pantulan
• Bina banteng tinggi.
• Air tidak melimpah ke jeti
• Bina jeti baru di teluk
• Air di teluk lebih tenang.
• Bina banteng dengan celah kecil di
sekeliling teluk.
• Pembelauan boleh berlaku di celah
supaya gelombang disebarkan. Tenaga
dan amplitude berkurang.

6. Pembelauan ialah penyebaran atau pembengkokan
gelombang apabila melalui celah atau halangan
Diffraction is the spreading or bending of waves as
it enter a gap or an obstacle.

7. Pembelauan kurang jelas. Tenaga atau
amplitud gelombang bertambah.
Less diffraction. Wave energy or amplitude
increases
Lebih banyak kerosakan pada pelabuhan.
More damage on the harbour.

8. Sumber yang hasilkan gelombang dengan
sama frekuensi dan beza fasa yang sama
Source that produce waves with same
frecuency and same phase different
• The ship moves up and down with
higher amplitude at A
• Constructive interference occurs at A
• The ship remain calm at B.
• Destructive interference occurs at B
• Kapal terumbang ambing di A
• Inteferens membina berlaku di A
• Kapal kekal pegun di B
• Inteferens memusnah berlaku di B

10. • Located at the bay
• Water is calmer
• Sloping retaining wall
• Slow down the speed as depth
decreases
• Uneven surface
• Absorb energy and reduce
amplitude of the wave
• High retaining wall
• Protect from high wave / prevent
water from overflowing
• Chose W
• Located at the bay, sloping retainin
wall, uneven surface and high
retaining wall
• Terletak di teluk
• Air tenang
• Tembok penahan bercerun
• Kurangkan laju bila kedalaman
berkurang
• Permukaan yang tidak rata
• Menyerap tenaga dan kurangkan
amplitud gelombang
• Tembok penahan tinggi
• Melindungi dari ombak tinggi /
elakkan air melimpah.
• Pilih W
• Terletak di teluk, tembok penahan
bercerun, permukaan tidak rata dan
tembok penahan tinggi

11. Frekuensi / panjang gelombang
Frequency / wavelength

12. • High pitch, high frequency / pitching
is directly proportional to frequency
• Frequency is inversely proportional to
wavelength / high frequency shorter
wavelength
• Short wavelength will diffract less, so
only student C can hear
• Sound easily diffracted during low
pitch sound which has low f, long λ so
students at A, B, C can hear.
• Kelangsingan tinggi, frekuensi tinggi.
• Frekuensi tinggi, panjang gelombang
pendek.
• Pembelauan kurang jelas jika panjang
gelombang pendek. Hanya pelajar C boleh
dengar
• Bunyi dengan kelangsingan rendah,
mempunyai frekuensi rendah.
• Maka λ panjang supaya bunyi lebih mudah
dibelaukan. ketiga2 pelajar boleh dengar.

15. Criteria Reason
1 Diameter besar 2 Menerima banyak isyarat
3 Sama dengan panjang
fokus
4 Isyarat difokuskan /ditumpukan ke
penerima // sinar selari
5 Microwave 6 Frekuensi tinggi // tenaga tinggi
7. Tinggi 8. Isyarat tidak dihalang
9. Pilih K
10. Kerana ia mempunyai diameter besar, sama dengan f, guna
mikrowave dan lokasi di tempat tinggi.

16. Criteria Reason
1 Large diameter 2 Receive ( more) signal
3 Same as focal length 4 Signal focused/ converge (to the
receivers // give out parallel beam
5 Microwave 6 Has high frequency // high energy //
7. High 8. The signal is not blocked
9. Choose K
10. Because it has large diameter, Same as focal length, use
microwave and locate at high position.

17. s = vt/2
v = 2s = 2 x 90 = 1500 ms-1
t 0.12
v = fλ
λ = 1500
50000
= 0.03 m // 3 cm

18. Panjang gelombang ialah jarak
antara dua puncak / lembangan
berturutuan.
Wavelength is the distance
between two successive
crest / trough

19. 1st : Panjang gelombang merah
lebih panjang.
2nd : jarak antara pinggir merah
dan hijau adalah sama.
3rd : Jarak antara dua pinggir
berturutan cahaya merah
lebih besar daripada cahaya
hijau.
4th : jarak antara pinggir-pinggir
bertambah bila panjang
gelombang bertambah
5th : Interferens

20. 1st : wavelength of red is larger
2nd : distance is equally space in
red fringe or green fringes
3rd : Distance between two
successive fringe of red is greater
than green.
4th : The fringes separation
increases with the wavelength
5th : Interference

21. 1st : Pada waktu malam, darat lebih
cepat sejuk
2nd : bunyi bergerak daripada udara
sejuk ke udara panas
3rd : laju bunyi bertambah.
4th : Gelombang bunyi dibias
menjauhi garis normal @
bengkok ke arah pemerhati.

22. 1st : At night, the ground cools
quickly
2nd : sound travels from cool air to
hot air
3rd : speed of sound increases
4th : Sound waves refract away
from normal line (bend
towards the observer )

24. Modification Reason
Pemantul parabolic
Parabolic reflector
Haba ditumpukan.
Heat will be focused
Permukaan berkilat / licin
Shining / smooth surface
Pantulan lebih berkesan
Reflection will be effective
Diameter besar
Larger diameter
Lebih banyak haba dapat
dikumpulkan
More heat will be collected
Diletakkan pada titik fokus.
Placed at the focal point
Haba ditumpukan ke cerek
Heat converge to kettle
Mengadap matahari
Facing the sun
Boleh kutip lebih banyak tenaga
solar.
Can collect/capture more solar
energy

25. 1. Gendang bergetar
2. Molekul2 udara bergetar
3. Hasilkan kawasan mampatan
dan regangan.
4. Arah getaran molekul udara
selari dengan arah perambatan
bunyi.
5. Tenaga dipindahkah.
6. Gegendang telinga bergetar.Gelombang membujur

26. 1. Drum vibrate
2. Air molecules vibrates
3. Produce compression and
rarefaction region
4. The direction of vibration of air
molecule is parallel to
the direction of propagation of
wave
5. Energy is transferred
6. Eardrum vibrates
Transverse wave

27. Panjang gelombang kawasan panas
lebih panjang.
Wavelength at warm region is longer
Sudut di kawasan panas lebih besar
Angle in warm region is bigger
Lebih panjang panjang gelembung,
lebih tinggi laju gelombang.
The longer the wavelength, the higher
the speed

28. Terbias menjauhi garis normal.
Refracted away from normal line.
pembiasan
Refraction.

30. Pancarkan gelombang
microwave
Transmit microwave
Mempunyai tenaga tinggi
Higher energy
Frekuensi lebih tinggi
Higher frequency
Tenaga tinggi supaya menembusi atmosfera
Higher energy so can penetrate atmosphera
Diameter penerima yang
besar
Large diameter of the receiver
Untuk menangkap / memantulkan banyak
isyarat
To capture / reflect more signal
Menggunakan stesyen geganti
/ satelit
Use relay station / satelite
Untuk mengatasi pelembapan
To overcome damping
Terletak di tempat tinggi.
Located on the higher position
Tiada halangan / liputan lebih luas
No blocking / wide coverage

31. Gelombang ultrasonic ialah gelombang
bunyi yang mempunyai frequency lebih
dari 20 000 Hz.
Ultrasonic wave is sound wave which has
frequency more than 20 000 Hz
1. Kelawar pancarkan gelombang ultrasonic.
The bat emits ultrasonic wave
2. Gelombang itu dipantulkan semula
oleh halangan.
The wave are then reflected back by the
obstacle
3. Masa antara pancaran dan penerimaan
gelombang dipantulkan di kesan.
The time between the emission and
reception of the reflected is detected
4. Semakin lama masa, semakin jauh
halangan. S = vt/2
The longer the time, the further the
obstacle s = vt/2

32. 1. 100 ms = 0.1 s
2. D = 1450 x 0.1 /2
3. = 72.5 m
1. λ = 1450 / 40 000
2. = 0.03625 m

34. 1. Pembesar suara diletakkan di tempat tinggi.
2. Untuk mengelakkan halangan
3. Jarak antara dua pembesar suara adalah besar.
4. Jarak antara dua bunyi berturutan / antinode, x kecil
5. Bahan digunakan untuk tutup dinding daripada papan lembut
6. Mengelakkan gema
7. Microphone diletakkan di belakang pembesar suara.
8. Untuk mengelakkan bunyi bising
9. Pilih Y
10. Tempat tinggi, jarak a besar, papan lembut, dan mikrofon
diletakkan di belakang pembesar suara.

35. 1. The loud speakers is put at high place
2. To prevent blocking
3. The distance between two loud speakers is large
distance
4. The distance between two loud sound is small
5. Soft board material
6. Avoid echo
7. Microphone is Behind the speaker
8. To avoid noise / humming
9. Choose Y
10. High place, large distance, soft board and
microphone behind the speakers