## Sunday, November 28, 2010

### SPM Trial MARA 2010 ~ paper 2 ( waves )

Diagram 8.1 shows Aini trying to open the house’s front gate using a remote control. Even though Amin is blocking her, the gate can still be opened.
Rajah 8.1 menunjukkan Aini cuba membuka pintu pagar rumah dengan menggunakan alat kawalan jauh. Walaupun Amin menghalangnya pintu pagar masih boleh dibuka.
(a)
(i)
Name the wave phenomenon involved
Namakan fenomena gelombang yang terlibat.

ii)
On Diagram 8.2, draw the wave pattern based on the situation in Diagram 8.1.

(b)
Table 8.1 shows the characteristics of three waves, X, Y and Z to be used in the remote control for the gate. Calculate the wavelength of each wave.
Jadual 8.1 menunjukkan ciri-ciri untuk tiga gelombang, X, Y dan Z yang akan digunakan dalam alat kawalan jauh bagi pintu pagar. Hitungkan panjang gelombang bagi setiap gelombang.

(i)
Wave X
Gelombang X

(ii)
Wave Y
Gelombang Y

(iii)
Wave Z
Gelombang Z

(c)
(i)
Based on your answers in 8(b), which wave is the most suitable to be used in the remote control for the gate?
Berdasarkan jawapan anda di 8(b), gelombang manakah yang paling sesuai digunakan untuk alat kawalan jauh bagi pintu pagar itu?

(ii)
State one reason for the answer in 8(c)(i).
Nyatakan satu sebab bagi jawapan 8(c)(i).

(d)
Based on the values of the wave speed shown in Table 8.1,
Berdasarkan nilai laju gelombang dalam udara yang ditunjukkan dalam Jadual 8.1,

(i)
Predict what wave X is.
Ramalkan gelombang X.

(ii)
State one application for wave X.
Nyatakan satu kegunaan gelombang X.

a)
i)
Diffraction of waves
ii)

b)

i) Velocity = Frequency × Wavelength
3.3 x 10 2 = 4. 0 x 105 x wavelength
wavelength = 8.25 x 10
-3 m

ii) wavelength = 0.75m

iii) wavelength = 7.5 x 1o -11

c)
i) wave Y

ii) The e of effect diffraction is very obvious.

d)

i) Sound wave

ii)Disintegration of kidney stones // Locating an object under water // remove plaque from teeth