Analysis Of The Daniell Cell

INTRODUCTION

For this laboratory experiment, the objectives are to describe the seats of electromotive force or EMF, and to know the difference between the EMF and terminal voltage. Also, one of the objectives of this experiment is to know the significance of internal resistance and how this internal resistance differentiate a real battery from an ideal battery. These objectives can be accomplished by knowing how to measure the EMF of a battery and by calculating the internal resistance of the battery.

A voltage or potential difference must be applied through a terminal coming from an external device or seats of EMF so current will flow through a resistor. The voltage, which is sustained transversely to the terminals, creates current

If the real battery is distributing power, the terminal voltage becomes:

V_ab=ε-Ir (eq. 1)

Deriving equation 1 to obtain the internal resistance gives us:

r=((ε-V_ab ))/I (eq. 2)

The Daniell cell was invented by John Frederick Daniell in 1836. It is a wet cell that can deliver constant electric current. The Daniell cell is made up of a pair of copper and zinc electrodes, and an electrolyte solution. Through redox reaction, the chemical energy is converted to electrical energy. The zinc-carbon battery, which is a dry cell, is also the common battery that we use in household products such as wall clocks, remote controls, etc. The internal resistance of the dry cell is expected to be lower than the Daniell cell.

METHODOLOGY

Daniell Cell (Wet Cell)

First of all, the voltage across the terminals was measured. The value obtained from this is equal to its EMF.

Then, the decade resistance box was set to 20Ω and connected to the

Also, how to calculate the internal resistance of a battery. It can be concluded in this experiment that the terminal voltage decreases as the current through it increases since power is being supplied by the battery.

REFERENCES

[1] Young, H., & Freedman, R. (2014). Current, Resistance, and Electromotive Force. In Sears and Zemansky's university physics with modern physics: Technology update. (13th ed., Pearson new international ed., Vol. 2). Harlow, Essex: Pearson Education

[2] Boundless. “EMF and Terminal Voltage.” Boundless Physics. Boundless, 21 Jul. 2015. Retrieved 14 Nov. 2015 from https://www.boundless.com/physics/textbooks/boundless-physics-textbook/circuits-and-direct-currents-20/resistors-in-series-and-parallel-151/emf-and-terminal-voltage-537-1104/

[3] EMF, Terminal Voltage, Internal Resistance. (n.d.). Retrieved November 14, 2015, from