6.In the streamlined flow of a liquid, the power due to pressure difference between the ends of the tube is

7.Three capillaries of internal radii 2r, 3r and 4r, all of the same length, are joined end to end. A liquid passes through the combination and the pressure difference across this combination is 20.2 cm of mercury. The pressure difference across the capillary of internal radius 2r is

8.A tank containing a liquid is emptied through an orifice in 9.8 second when placed on the ground. If this tank is placed at at height of 9.8 metre above the ground, it would be emptied in

9.A water tank placed on the floor has two small holes, pinched in the vertical wall, one above the other. The holes are 3.3 cm and 4.7 cm above the floor. If the jets of water issuing out from the holes hit the floor at the same point on the floor, then the height of water in the tank is

10.A ball rises to the surface of a liquid with constant velocity. The density of the liquid is four times the density of the material of the ball. The frictional force of the liquid on the rising ball is greater than the weight of the ball by a factor of