36. The phase difference between driving force and displacement of driven harmonic oscillator in high driving frequency condition is (1) 0 (2) 90 (3) 180 (4) 270 37. The correct relationship between the phase velocity Vp and the group velocity Vis (1) V=Vp g (2) VpVg- = dVp dV d dVp (3) V=Vp+d 1 dVp (4) VpVg d 38. The speed of sound in water is 1346 m/s and density of water is 1000 kg/m, then the bulk modulus of elasticity of water is nearly (in N/m) (1) 107 (2) 108 (3) 0.9109 (4) 1.8 109 39. The volume of hollow hall is 2000 m and total absorption coefficient is 165 unit. Then reverberation time of hall is (1) 4s (3) 1s (2) 2s (4) 0.5s 40. The musical interval between any two consecutive tones in a 12 - ET tempered musical scale is (1) 21/6 (3) 21/13 (2) 21/12 (4) 21/11