1. Three masses M = 100kg, m = 10kg and M = 20kg are arranged in a system as shown in figure. All the surface are frictionless and strings are inextensible and weightless. The pulleys are also weightless and frictionless. A force F is applied on the system so that the mass m2 moves upward with an acceleration of 2ms. The value of F is: (Take g = 10ms ) (a) 3360 N (b) 3380 m = 10kg F M = 100kg m2 = 20kg (c) 3120 N (d) 3240 N 2. A radio can tune to any station in 6 MHz to 10 MHz band. The value of corresponding of wavelength bandwidth will be: (a) 4m 3. (b) 20m (c) 30m (d) 50m The disintegration rate of a certain radioactive sample at any instant is 4250 disintegrations per minutes later, the rate becomes 2250 disintegrations per minute. The approximate decay constant is: 4. 5. (Take log10 1.88 = 0.274) (a) 0.02 min 1 (b) 2.7 min1 (c) 0.063 min 1 (d) 6.3 min1 A parallel beam of light of wavelength 900nm and intensity 100Wm2 is incident on a surface perpendicular to the beam. The number of photons crossing 1cm area perpendicular to the beam in one second is: (a) 3 1018 (b) 4.5 x 1016 (c) 4.5 x 1017 (c) 4.5 x 1020 In Young's double slit experiment, the fringe width is 12mm. If the entire arrangement is placed in water refractive index, then the fringe width becomes (in mm): 3 (a) 16 (b) 9 (c) 48 (d) 12