State the principle of working of a potentiometer. Give its application to measure potential difference and to compare emf of two cells.

Write the principle of preparation of bakelite. Give its two uses.

State the principle of superposition of potentials. Find an expression for the potential at a point due to an electric dipole on its axis, if P is electric dipole moment.

State and explain 2nd law of thermodynamics. Give it’s practical applications.

Give two applications of the principle involved in bernoullie's equation.