A long solenoid of radius `3cm` , length `I00cm` carries a current of `4A` . The total number

A long solenoid of radius `3cm` , length `I00cm` carries a current of `4A` . The total number of truns is `300` . Assuming ideal solenoid, find the flux passing through a circular surface having centre on axis of solenoid, (a) of radius `2cm` and is perprndicular of the axis of solenoid (i) inside and (ii) at the end of solenoid (b) of radius `4cm` and is perprndicular of the axis of solenoid (c) of radius greater than `3cm` and angle between normal to area and axis of solenoid is `60^(@)C`