TF3103 Fenomena Gelombang
Solusi Take Home Test
Dosen: Dr. Suprijanto, Iwan Prasetiyo,Ph.D,
Soal Dikirimkan:
Dikumpulkan paling lambat:
Nama file: Azizah_13319045_PR1_Fenom
Nama : Azizah
NIM: 13319045
Alamat Email : Azizahhafid34@gmail.com
Tanda tangan :
Soal 1 : A 1 kHz plane wave in water of 50 Pa effective (rms) pressure is incident normally on the water-air
boundary.
(a). What is the effective pressure of the plane wave transmitted into the air
(b). What is the intensity of the incident wave in the water and of the wave transmitted into the air
(c). Express, as a decibel reduction, the ratio of the intensity of the transmitted wave in air to that the incident
wave in water
Jawab :
Soal 2:
(a). A plane wave in seawater in normally incident on the water-air interface. Find the pressure and intensity
transmission coefficients
(b). Repeat (a) for a wave in air normally incident on the air – water interface
(c). For (a) and (b) find the change in pressure and intensity level if Pref and Iref are the same in both media
Jawab:
Soal 3:
Suatu gelombang akustik berfrekuensi 25 kHz akan ditransmisikan dari air (998 kg/m3 , 1481 m/s) ke baja (7700
kg/m3 , 5850 m/s). Agar tidak ada daya suara yang dipantulkan, maka baja tadi dilapisi dengan suatu bahan plastik
yang mempunyai rapat massa sebesar 1500 kg/m3 . Bila kemudian gelombang akustik yang akan ditransmisikan
berfrekuensi sebesar 20 kHz, tentukan berapa dB kehilangan transmisinya (Transmission Loss).
Jawab:
Soal 4:
Suatu gelombang akustik merambat melalui tiga medium, yaitu plastik (plastik = 1180 kg/m3 , cplastik = 2670
m/s), baja (baja = 7800 kg/m3 , cbaja = 5850 m/s) dan air (air = 998 kg/m3 , cair = 1481 m/s). Bila sudut datang
pada bidang batas plastik-baja adalah 15o a) Hitung sudut bias pada bidang batas baja-air. b) Hitung persentase
intensitas yang diteruskan ke air
Jawab: