Online test

1. The potential energy between two atoms in a molecule is given by U (x) = ; where a and b are positive constants and x is the distance between the atoms. The atom is in stable equilibrium when : (A) x = (B) x = (C) x = 0 (D*) x = 2. Two identical cylindrical vessels with their bases at same level each contains a liquid of density . The height of the liquid in one vessel is h1 and that in the other vessel is h2. The area of either base is A. The work done by gravity in equalizing the levels when the two vessels are connected, is : (A) (h1 – h2)g (B) (h1 – h2)gA (C) (D*) 3. What is the velocity of the bob of a simple pendulum at its mean position, if it is able to rise to vertical height of 10 cm (Take g = 9.8 m/s2) : (A) 0.6 m/s (B*) 1.4 m/s (C) 1.8 m/s (D) 2.2 m/s 4. Which of the following graphs is correct between kinetic energy (E), potential energy (U) and height (h) from the ground of the particle : (A*) (B) (C) (D)