Why should emf of cell in the secondary circuit be less than the emf of the battery in the primary circuit?
A: The emf of the cell in secondary circuit must be less than emf of cell in primary circuit in potentiometer. R: Balancing length cannot be more than length of potentiometer wire. The balancing length will be [cell in primary is ideal and no series resistance is present in primary circuit.]
What would happen if the emf of driving cell is less than experimental cell?
If the emf of the driving cell is decreased, the potential gradient across the potentiometer wire will decrease. Due to it, the position of zero deflection will be obtianed on longer length.
What will happen if the PD of the driver cell is less than the PD of the experimental cell in a potentiometer experiment?
Solution : If either the e.m.f. of the driver cell or potential difference across the whole potentiometer wire is lesser than the e.m.f. of the experimental cell, then balance point will not obtained.
Can emf of driving cell be less than emf of primary cell?
The emf of the driver cell in the potentiometer experiment should be greater than the emf of the cell to be determined.
Why does the EMF of a battery decrease as it is used?
The electric potential increases the emf of the battery due to the chemical reactions doing work on the charges. There is a decrease in the electric potential in the battery due to the internal resistance.
Is EMF really a force explain?
The work done on a unit of electric charge, or the energy thereby gained per unit electric charge, is the electromotive force. Electromotive force is the characteristic of any energy source capable of driving electric charge around a circuit. Despite its name, electromotive force is not actually a force.
Why do driver cells have emf?
The emf of the driver cell in the potentiometer experiment is greater than the emf of the cell to be measured because , If not, then there will be a small potential difference across the potentiometer wire and balancing point will not be obtained.
Why do we prefer a potentiometer with longer wire?
A potentiometer with longer bridge wire will have a small potential gradient. Due to it, it becomes more sensitive. Hence it is preferred.
Why do we prefer potentiometer of longer length for accurate measurements?
The potential gradient can be made quite small more conveniently by using a long wire as compared to a potentiometer of small wire. If Potential gradient is small, the balancing length for a particular unknown potential difference is more. Thus, the percentage error in balancing length is reduced.
Why is electromotive force important?
The emf source acts as a charge pump, moving negative charges from the positive terminal to the negative terminal to maintain the potential difference. This increases the potential energy of the charges and, therefore, the electric potential of the charges.
Does the EMF of battery decrease over time?
As the chemical energy in a battery is used up, processes internal to the battery appear like a resistor is series to the battery. The conductivity of the cell decreases. Cell EMF does not change.
Is every EMF a potential difference is every potential difference and EMF?
Electromotive force (EMF) is equal to the terminal potential difference when no current flows. EMF and terminal potential difference (V) are both measured in volts, however they are not the same thing. EMF (ϵ) is the amount of energy (E) provided by the battery to each coulomb of charge (Q) passing through.
What should be the emf of the driver cell in potentiometer?
The emf of the driver cell in the potentiometer experiment should be greater than the emf of the cell to be determined. > The emf of the driver cell The emf of the driver cell in the potentiometer experiment should be greater than the emf of the cell to be determined.
What happens if the potential difference is less than the EMF?
The fall of potential across the potentiometer wire should not be less than the emf of the cell to be determined. If either the emf of the driver cell or the potential difference across the whole potentiometer wire is lesser than the emf of the experimental cell, the balance point will not be obtained.
What is the emf of the driver cell of a capacitor?
EMF of the driver cell should be higher than the e.m.f.s of each of the two cells being compared to obtain the balance point.Otherwise, null point or balanced point cannot be obtained. Because the max. potential difference across the resistance wire of potentiometer is the emf of driver cell.
Why Balance Point is not obtained in potentiometer?
If either the emf of the driver cell or the potential difference across the whole potentiometer wire is lesser than the emf of the experimental cell, the balance point will not be obtained. The balance point indicates that emf of the cell to be determined is just balanced by the voltage drop appears across the wire.