Which of the following is the only incorrect statement ?

[IIT 2006]

(A) For the gas (A) ; a = 0 and it dependence linearly with P at all pressure value
(B) For the gas (B) , b = 0 & its dependence linearly with pressure at all pressure value
(C) C represent a typical real gas for which neither a nor b is equal to 0. If minima & the point of intersection is known with Z = 1, a & b can be calculated
(D) At high pressure the slope is positive for all real gas
[NOTE: If you answer these this question, please give a brief explanation for the answer.]

Three identical balls are placed on a frictionless horizontal surface touching each other. They stick to each other because of adhesive. Another ball of same radius and mass m is placed over the void created by the three balls. Find the forces applied by the balls kept on the floor to each other if the system remains in equilibrium.

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

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