nanangnurulhidayat
23. diketahui : λ = 500 nm = 5 x 10⁻⁷ m = 5 x 10⁻⁵ cm θ = 30° n = 4 (terang) ditanya : N = .... garis/cm dijawab : N = sin 30° / nλ = (1/2) / (4 x 5 x 10⁻⁵) = 10⁵ / 40 N = 2500 garis/cm (jawaban : B)
24. Vs = 80 Hs fs = 780 Hz fp = 1080 Hz v = 340 m/s ditanya : vp = ... ? dijawab :
θ = 30°
n = 4 (terang)
ditanya : N = .... garis/cm
dijawab : N = sin 30° / nλ
= (1/2) / (4 x 5 x 10⁻⁵)
= 10⁵ / 40
N = 2500 garis/cm (jawaban : B)
24. Vs = 80 Hs
fs = 780 Hz
fp = 1080 Hz
v = 340 m/s
ditanya : vp = ... ?
dijawab :
fp = (v+vp) fs / (v-vs)
1080 = (340+vp) 780 / (340-80)
1080 = (340+vp) 780 / 260
1080/3 = 340 +vp
360 = 340 + vp
vp = 20 m/s (jawaban : B)
25. diketahui : n₁ = 100
TI₁ = 90 dB
n₂ = 10
ditanya : TI₂ = ... ?
dijawab : TI₂ = TI₁ + 10 log (n₂/n₁)
= 90 + 10 log (10/100)
= 90 - 10
TI₂ = 80 dB (jawaban : E)