13. An ideal gas undergoes a cyclic process whose indicator diagram is as shown in the figure. Find the work done by the gas in 1 complete cycle. 10 atm P sha (a) 4 lt - atm (Pressure) 6 atm 21t 6lt Volume (1) (b) 16 lt-atm (c) 8 lt-atm (d) 16 It - atm 14. A rod of mass m and length L is hinged at its top end. If the rod is in equilibrium making an angle of 30 with the vertical when a horizontal force F is applied as shown in figure, then the value of F is: (a) mg/2 (b) 2mg H 30 (c) mg/23 (d) 3mg Abhishek and Deepak have two samples of magnetic materials X and Y. Experimentally they determine the following properties of the samples. Retentivity X 1.5 T Y 1.0 T Coercivity 20 Am 100 Am Considering this, choose best choice (a) X and Y both for electromagnets (b) X for electromagnetic and Y for permanent magnets (c) X and Y both for permanent magnets (d) X for permanent magnets and Y for electromagnets 16. In free space, two particles of mass m each are initially both at rest at a distance a from each other. They start moving towards each other due to their mutual gravitational attraction. The time after which the distance between them has reduced to is 2 (a) +2 a 42 Gm 1/2 1/2 -2 (b) +2 a 3 1/2 - -2 42 (c) (d) Gm 8 Gm 8 Gm