11. In a common emitter amplifier circuit using an n-p-n transistor, the phase difference between the input and the output voltages will be: (1) 135 (3) 45 (2) 180 (4) 90 12. C and C, are specific heats at constant pressure and constant volume respectively. It is observed that C-C, a for hydrogen gas C-C=b for nitrogen gas The correct relation between a and b is: (1) a=14b (2) a=28b (3) a= -b (4) a=b 14 13. A copper ball of mass 100 gm is at a temperature T. It is dropped in a copper calorimeter of mass 100 gm, filled with 170 gm of water at room temperature. Subsequently, the temperature of the system is found to be 75C. T is given by (Given: room temperature=30 C, specific heat of copper = .1 cal/gmC (1) 1250C (2) 825C (3) 800C (4) 885C 14. A body of mass m = 10-2 kg is moving in a medium and experiences a frictional force F=-kv. Its intial speed is vo 1 = 10 ms 1. If, after 10 s, its energy is - m, the value of k will be: (1) 104 kg m-1 (3) 10-3 kgm1 8 (2) 10kg ms (4) 103 kg s 15. When a current of 5 mA is passed through a galvanometer having a coil of resistance 15 Q2, it shows full scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into to voltmeter of range 0-10 Vis (1) 2.53510 (2) 4.005 10 (4) 2.045 10 (3) 1.98510 16. A slender uniform rod of mass M and length is pivoted at one end so that it can rotate in a vertical plane (see figure). There is negligible friction at the pivot. The free end is held vertically above the pivot and then released. The angular acceleration of the rod when it makes an angle with the vertical is (1) 38 cost 2g 3g 28 cose (2) (3) 38 sine 28 si (4) -sine 20 2l