Question

The terminal voltage of a cell in open circuit condition is
A. Less than its emf
B. More than its emf
C. Equal to its emf
D. Depends on its internal resistance

Answer 1

Hint: To solve this question we have to know about emf. We know that, EMF is the ordinarily utilized abbreviation for electromotive power. A generator or a battery is utilized for the change of energy starting with one structure then onto the next. The electromotive force formula can also be written as, \[e{\text{ }} = {\text{ }}IR{\text{ }} + {\text{ }}Ir\;{\text{ }}or,{\text{ }}e{\text{ }} = {\text{ }}V{\text{ }} + {\text{ }}Ir\].

Complete step by step answer:
The terminal voltage of a cell in open circuit condition will be equal to emf of the cell as the circuit is open there won’t be any drop across the internal resistance. Internal resistance alludes to the resistance to the progression of current offered by the cells and batteries themselves bringing about the age of warmth. Inner opposition is estimated in Ohms.

We can say, as current moves through the inward obstruction, some energy is changed over from electrical to warm inside the cell (so the cell gets hot). That outcomes in an expected drop across the interior opposition of the cell. This implies that there is less energy to be changed over to warm in the resistor.
We know that, \[e = E/Q\]
Here, $Q$ denotes charge and $e$ denotes emf.

So, the correct answer is option C.

Note: We also can say, The electromotive force (EMF) is described as the electrical potential created either by an electrochemical cell or by an attractive field change. The broadly utilized shortened term for electromotive power is EMF. Both electromotive force and potential difference are measured in volt. We have to keep that in our mind.