1. 2. A plastic circular disc of radius 10cm is placed on a thin oil film of thickness 2mm, spread over a flat horizontal surface. The torque (N-m) required to spin the disc about its central vertical axis with a constant angular velocity 8 rad/sec is (coefficient of viscosity of oil is 1.0 kg/m-s) (take = 3.14) Calculate the value of output voltage Vo (in V) if the Si diode and Ge diode conduct at 0.7V and 0.3V respectively as shown in figure. 12V ++ Ge Vo Si 5 kha 3. 4. In Young's double slit experiment, the wavelength of red light is 7800 and that of blue light is 5200 . minimum value of n for which nth bright band due to red light coincides with (n + 1) th bright band due to blue light, is: A railway track (made of iron) is laid in winter when the average temperature is 18C. The track consists of sections of 12.0m placed on after the other. How much gap (in cm) should be left between two such sections so that there is no compression during summer when the maximum temperature goes to 48C? Coefficient of linear expansion of iron = 11 10/C.