- (B) Work done by gravity is negative because the gravitational force opposes the upward motion.
- (E) Work done by air resistance is always negative because it opposes motion.
- Other statements are incorrect because:
- (A) Work done by a man is positive as the applied force is in the direction of displacement.
- (C) Work done by friction is negative, not positive.
- (D) Work done is zero only if there is no displacement, not due to roughness.

Potential energy (V) versus distance (x) is given by the graph. Rank various regions as per the magnitudes of the force (F) acting on a particle from high to low. 
Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?

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