Question

Figure 2: Problem 17 17. The curve in Fig. 2 that represents the speed of sound in a gas plotted against absolute temperature is A) 3 B) 5 C) 1 D) 2 E) 4 18. A sinusoidal wave train is moving along a string. The equation giving the displacement y of a point at coordinate z has the form :)- v(r, t) = 6m sin 25 60 m where m ands are SI units. Find the wavelenth. A) m B) m C)m D) m E) Tm 19. If a sound of intensity 5.0 W/ m2 falls on a detector of area 8.0 mm2 (about the size of your eardrum), how much power is received by the detector? A) 4.00e-05 W B) 2.00e-05 W C) 3.00e-05 W D) 6.00e-05 W E) 1.00e-04 W 20. A passenger car traveling due east at 85 m/s passes a truck traveling due east at 35 m/ s. After the car passes, the horn on the truck is blown at a frequency of 230 Hz. The speed of sound in air is 336 m/ s. The frequency heard by the driver of the car is A) 261 Hz B) 156 Hz C) 322 Hz D) 192 Hz E) 276 Hz

Answer 1

Soen: (18) y(xit) = 6m Sim [2594 - 253 ] Comparing with y= Asin (wt -ka), we get K=255 60 Since, K= 20) = x=25 = 20 x 60 250 = 24 m la wavelength 14) I= 56m2 , A = 8x10-6 m2 tot power, P= IA = 5x8x10-6 W j |P=4x10-5 watt

(20) speed of observo, Vo = 85 m/s. speed of source, Ve = 35 mols do= 230 HZ sound -VD do 251 +230 (sound - Vs J 301 d'=19242