Which metal pairs when coupled will get maximum emf for a voltaic cell

What is the relationship between Gibbs free energy of the cell reaction in a galvanic cell and the emf of the cell ? When will the maximum work be obtained froma galvanic cell ?

What is the relationship between Gibbs free energy of the cell reaction in a galvanic cell and the emf of the cell? When will the maximum work be obtained from a galvanic cell?

When an electric dipole is placed in a uniform electric field, a couple acts on it. The moment of couple will be maximum when the dipole is placed

When an electric dipole is placed in a uniform electric field, a couple acts on it. The moment of couple will be maximum when the dipole is placed

Which of the following is secondary voltaic cell?

For a given temperature difference, which of the following pairs will generate maximum thermo e.m.f.