Quick Answer: On What Factors EMF Of A Cell Depends?

On what factors internal resistance of a cell depends?

That is, internal resistance depends on the nature of the electrolyte.

The internal resistance of a cell is inversely proportional to the common area of the electrodes dipping in the electrolyte.

The internal resistance of a cell depends on the nature of the electrodes..

How does internal resistance of a cell vary with temperature?

On increasing temperature , in electrolytes, there is increase in thermally generated electrons over the existing ions, so the internal resistance will decrease with the increase of temperature and increase with the decrease of temperature.

Does a 1.5 V battery have an internal resistance?

3. Does a 1.5 V battery have an internal resistance? If the maximum current the battery can supply is 200 mA, what is the value of its internal resistance? Solution: Yes, it has an internal resistance which is very small.

What affects internal resistance?

In practice, the internal resistance of a battery is dependent on its size, state of charge, chemical properties, age, temperature, and the discharge current.

What is emf and terminal voltage?

electromotive force (emf): the potential difference of a source of electricity when no current is flowing; measured in volts internal resistance: the amount of resistance within the voltage source potential difference: the difference in electric potential between two points in an electric circuit, measured in volts …

How many ohms does a 12 volt battery have?

500 ohmsThe resistance “seen” by the 12-Volt battery is 500 ohms . The total resistance is the sum of the resistors R1 and R2. Each resistor will drop a calculable amount of voltage. This voltage is given by Ohm’s Law.

What is the internal resistance of a 12v car battery?

12.5 ohmsThe resistance R is equal to square of 5 volts divided by 2 watts, which is equal to 12.5 ohms.

How EMF of a cell is measured?

The EMF of a galvanic cell is measured by The potential differnce of a cell when no current is drawn out and when the cell is operating reversibly (i.e., very-2 slowly) is called the emf (electromotive force) of the cell. The measurement of the emf can by done by using a pote-tiometer.

What happens when internal resistance increases?

High resistance, current is restricted, voltage drops on load; battery heats up. Figure 1: Effects of internal battery resistance. A battery with low internal resistance delivers high current on demand. High resistance causes the battery to heat up and the voltage to drop.

What is the difference between resistance and internal resistance?

Internal resistance is the resistance within a battery, or other voltage source, that causes a drop in the source voltage when there is a current. … External resistance or simply called Resistance is generally referred as the opposition to the flow of current offered by any load.

Does EMF depend on temperature?

The Emf of a cell is measured at several temperatures. On the basis of these measurements, the enthalpy, entropy and free energy changes are found for the cell reaction. … The emf produced by an electrochemical reaction will generally change with temperature.

What is EMF of a cell?

The electromotive force (emf) is the sum of the electric potential differences produced by a separation of charges (electrons or ions) that can occur at each phase boundary (or interface) in the cell. The magnitude of each potential difference depends on the chemical nature of the two contacting phases.

What is internal resistance of the cell?

Internal resistance refers to the opposition to the flow of current offered by the cells and batteries themselves resulting in the generation of heat. Internal resistance is measured in Ohms. … Example: 1 The potential difference across the cell when no current flows through the circuit is 3 V.

What four factors affect the induced emf?

Minimum things required to induce emf are conductor , flux and movement of conductor in magnetic field. From this equation it can be seen that induced emf depends upon flux density, effective length of conductor, velocity of conductor and angle between velocity direction and flux direction.

How do you increase EMF induced in a coil?

Increasing the number of turns of wire in the coil – By increasing the amount of individual conductors cutting through the magnetic field, the amount of induced emf produced will be the sum of all the individual loops of the coil, so if there are 20 turns in the coil there will be 20 times more induced emf than in one …

Can you have negative EMF?

The voltage is not negative, always. The negative sign in Faraday’s law (Lenz’s law) does not mean that the EMF (or current) always points in some “negative” direction. It means that the current always flows in a way to oppose the change in flux, which is nicely illustrated in that video clip.

Does induced emf depend on resistance?

From the formula, it is evident that the induced EMF does not depend on the resistance of the coil or wire. … The produced current will result in a tendency to oppose the induced EMF, thereby in a tendency to oppose the rate of change of the flux (Lenz’s Law), as a result of which the induced EMF will be decreased.

Is terminal voltage greater than EMF?

If, on the other hand, the battery is being charged by an external source such as a recharger, the current will be forced through the battery in the opposite direction; the terminal voltage will then be higher than the emf by the amount of the voltage difference across its internal resistance.

What is the formula for induced emf?

An emf induced by motion relative to a magnetic field is called a motional emf. This is represented by the equation emf = LvB, where L is length of the object moving at speed v relative to the strength of the magnetic field B.

How can the internal resistance of a cell be reduced?

decrease the distance between the anode and the cathode; 2. increase the surface of the electrodes available for biofilm growth; 3. eventually change the electrodes material to more conductive ones (and with higher specific surface); 4. increase the surface of the ionic exchange membrane (if present); 5.

What is the standard EMF?

The cell potential is the difference between the electrode potentials (reduction potentials) of the cathode and anode. It is called the standard electromotive force (emf) of the cell when no current is drawn through the cells.