46. An open-ended cardboard tube has a length of 67 cm. Upon sonically exciting the tube, the fundamental frequency one would get to hear at the other end will be (speed of sound = 343m/s) A) 128 Hz 47. 48. 49. B) 256 Hz C) 64 Hz In which of the following decays, the atomic number decreases A) + decay B) decay C) y decay D) 512 Hz D) v decay Heavy water (DO) is used in thermal neutron reactors as a moderator for A) reducing the rate of release of fission energy B) moderating the temperature of the core of the nuclear reactor C) acting as intermediate absorbers of the neutrons D) slowing down fast fission neutrons to thermal energy. Cp and C, denote the molar specific heats of a gas at constant pressure and at constant volume respectively. Cp/C = 5/3 and Cp - C = R, then C, is equal to A) 0.5 R B) 2.5 R C) 1.5 R D) 0.66 R 50. The molar mass of gas molecules is denoted by m and p is the density of gas and N is the Avogadro's number. Then number density of gas molecules confined in box of volume V is given by ----. A) m/(p Na) B) p N/m C) p /Nam D) p Nam