What is constant in a battery (also called a source of emf)?

Name a source of emf.

What is called as battery arm ?

Molal clevation constant is also called as

The propagation constant of a wave is also calle its

The propagation constant of a wave is also calle its

Is it possible that any battery has some constant valur of emf, but the potential difference between the plates is zero?

Why the induced emf is also called as back emf?

The universal gas constant (also called molar gas constant ) R is equivalent to