# Ringkasan

### Ringkasan

##### A. Cepat Rambat Gelombang Bunyi

$$v = \sqrt{\dfrac {E}{\rho}}$$

$$v = \sqrt{\dfrac {B}{\rho}}$$

$$v = \sqrt{\gamma \:.\: \dfrac {P}{\rho}}$$

$$v = \sqrt{\gamma \:.\: \dfrac {R \:.\: T}{M}}$$

v (zat padat) > v (zat cair) > v (zat gas)

##### B. Interferensi

Konstruktif (kuat)

$$\Delta s = n \:.\: \lambda$$

$$n = 0, 1, 2, 3, \dotso$$

Destruktif (lemah)

$$\Delta s = (n + \frac 12) \:.\: \lambda$$

$$n = 0, 1, 2, 3, \dotso$$

##### C. Efek Doppler

$$f_p = \dfrac {v \pm v_p}{v \pm v_s} \:.\: f_s$$

Pedoman menentukan tanda (+) dan (−)

Apabila pendengar/sumber mendekat, maka frekuensi pendengar akan bertambah besar.

Sebaliknya, apabila pendengar/sumber menjauh, maka frekuensi pendengar akan bertambah kecil.

##### D. Dawai/Senar

Cepat rambat gelombang bunyi pada dawai

$$v = \sqrt{\dfrac {F}{\mu}}$$ dimana $$\mu = \dfrac mL$$

$$v = \sqrt{\dfrac {F}{\rho \:.\: A}}$$

Frekuensi nada dasar ($$f_o$$)

$$f_o = \dfrac {v}{2L}$$

$$f_o : f_1 : f_2 : f_3 = 1 : 2 : 3 : 4$$

$$L = \frac 12 \lambda$$

$$\lambda = 2 L$$

$$L = \lambda$$

$$L = \frac 32 \lambda$$

$$\lambda = \frac 23 L$$

##### E. Pipa Organa

Pipa organa terbuka

$$f_o = \dfrac {v}{2L}$$

$$f_o : f_1 : f_2 = 1 : 2 : 3$$

Pipa organa tertutup

$$f_o = \dfrac {v}{4L}$$

$$f_o : f_1 : f_2 = 1 : 3 : 5$$

Gelombang stationer pada pipa organa terbuka

$$L = \frac 12 \lambda$$

$$\lambda = 2 L$$

$$L = \lambda$$

$$L = \frac 32 \lambda$$

$$\lambda = \frac 23 L$$

Gelombang stationer pada pipa organa tertutup

$$L = \frac 14 \lambda$$

$$\lambda = 4 L$$

$$L = \frac 34 \lambda$$

$$\lambda = \frac 43 L$$

$$L = \frac 54 \lambda$$

$$\lambda = \frac 45 L$$

##### F. Layangan

$$f_L = | \: f_1 - f_2 \: |$$

##### G. Intensitas Dan Taraf Intensitas

Intensitas bunyi

$$I = \dfrac {P}{A}$$ ... W/m²

P = daya sumber bunyi ... Watt

A = luas permukaan = 4 π R²

Perbandingan Intensitas bunyi

$$\dfrac {I_1}{I_2} = \left( \dfrac {R_2}{R_1} \right)^2$$

Taraf Intensitas bunyi

$$TI = 10 \:.\: \log \left (\dfrac {I}{I_o} \right)$$ ... dB

Io = intensitas ambang bunyi = 10−12

Taraf Intensitas n buah sumber bunyi

$$TI_n = TI_1 +\log n$$

$$TI_2 = TI_1 +\log \left( \dfrac {R_1}{R_2} \right)^2$$