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Factors That Affect Level of resistance and Electric Power

A report in to the electricity practical analysis and problems

  • Samerah Mansha


This test was regarding electricity and its features. The experiment establishes factors that have an impact on resistance and energy. The results revealed that by increasing the amount of light bulbs within the electric circuits affected both electric power and resistance value in both series and parallel circuits.


The opportunity of the inspection was to learn the factors that affect resistance in just a circuit by creating series and parallel circuit's whilst differing the amount of bulbs used. On top of that, a voltmeter was connected within to gauge the electric powered potential difference in volts between two tips within the circuit. An ammeter was also used to gauge the current in amps within the circuit.

Direct current is known as the continuous movements of electrons from areas surrounded with negative fee to areas surrounded with positive charges through the conducting materials such as metal line. Whilst the intensity of current may differ the general path of movement stays the same throughout. One common example of a direct current is a power supply.

Parallel circuits and series circuits are two basic types of electric circuits that may be found within electrical devices. They both change in conditions of where the components are put within circuit

In series circuits there are no branches present thus components are connected one after another in a single pathway, allowing current to follow the circuit from one part to the other area of cell moving through each one of the components, one following the other. In a string circuit, if a lamp breaks or even a element is disconnected, the circuit is busted leading to all the components within to avoid working. The current within series circuit is found to be the same everywhere within the circuit, whilst the voltage is shared in percentage to level of resistance.

Figure: 1 an example of series circuit.

In a parallel circuit, there are multiple pathways between circuit's beginning and end, whilst different components are linked into different branches of the line.

Therefore the electric current has more than one route to take, thus circuit gets the potential to still function even if one journey fails, for example in case a lamp breaks or an element is disconnected in one parallel line, the components on different branches are still able to work therefore parallel circuits are additionally used in home applications. It doesn't matter how many different paths the circuit has, the full total voltage stays the same, as the voltage across each pathway equals to the source voltage. The current through parallel circuits splits up as it moves through the passageways.

Figure: 2 - an example of a parallel circuit

Electromotive force abbreviated as e. m. f is when charge flows through the cell or electric battery, it is given energy. The number of joules of energy given to each coulomb of charge that goes by through the cell is known as called e. m. f. of cell which is measured in volts (V). It is equal to the difference over the terminals of the cell when no current is flowing. Examples of resources of e. m. f are skin cells, batteries and generator

Potential difference (p. d) is known as the amount of electricity that is changed into other types of energy per coulomb of demand. In circuits there are components that put energyinto the circuit and components that take energyout. Any device adding energy into circuit is providing an e. m. f whilst any device taking energy out has p. dacross it. The p. d across an electrical component is required to make current movement in it. Skin cells or batteries tend to be in charge of the p. d needed. P. d is assessed in volts by using a voltmeter.

Electrical cells are produced from materials and chemicals, that have some sort of resistance. Therefore, a batteries and skin cells must have amount of resistance known asinternal level of resistance which ismeasured in ohms. When electricity flows round a circuit the inner resistance of the cell itself causes a drop in soruice of voltage whilst resisting the movement of current thusthermalenergy is wasted in the cell itself.

Ohms law is often used to portray that current streaming through a metallic wire is proportional to the difference across it, providing that heat range remains constant.

Resistance is assessed in ohms. Оrthus increased the number of ohms, the greater the resistance.

The relationship between voltage, current and resistance is V= IR, Potential difference (volt, V) = current (ampere, A) amount of resistance (ohm, О).

Figure: 3 - Graph showing the relationship between current and voltage following Ohm's Legislation that electric current is proportional to voltage and inversely proportional to resistance Energy is the speed of energy use and the way electric energy is moved n in a electronic circuit. The electric power is assessed in watts.



  • Locktronics electricity kit
  • Bulbs
  • Ammeter
  • Voltmeter
  • Wires
  • Electric Source

Safety Measures:

As the mains voltage electricity was used throughout the test, it was dangerous. Thus significant risk of electrocution may occur if mains voltage electricity is allowed to pass through the body. The mains voltage was made sure it was switched of when connecting wire connections and components along. There may be a risk of fireplace and explosion if electricity is not cabled and fused properly and if in close proximity to water. Therefore safeguards were used when mains electricity was. Before any equipment was used they were checked out to see any visible harm to the leads and equipment.


  • Firstly a simple series circuit was conducted out using an locktronics electricity kit is which simplifies the process of learning electricity using wiring, mains source, voltmeter, ammeter and one light bulb.
  • Secondly, 3 other simple series were conducted out just as each increasing the amount of lights used.
  • Lastly, 3 clothes circuits were produced using the same method as above each increasing the quantity of lights used within.
  • In each of the series and parallel circuits, the voltage and current was measured.
  • Using the measurements of voltage and current, the beliefs of amount of resistance and electrical power was computed.


Series Circuits

Number Of bulbs




0. 09



0. 06



0. 04



0. 04



Parallel Circuits

Number Of bulbs




0. 1



0. 18



0. 26



See results 5, 6, and 7

The results for the series circuits show that as the number of bulbs increase, the worthiness current and voltage cut down. Apart from 3 light bulbs for series circuit the worthiness of amperes should be less as it doesn't participate in the general tendency.

Whereas the in the parallel circuits as the amount of bulbs increase the current lower, whilst the voltage remains the same.


The principles of level of resistance and electrical energy have been calculated. (see number).

The conclusions show that for the series circuits show that as the number of bulbs increases the value of power and resistance both lower. However, when there were 3 and 4 light bulbs within the circuit the worthiness of resistance continued to be the same within the circuit which doesn't fit in with the general trend, therefore figure three or four 4 may be an anomaly.

The calculations show for the parallel circuits show that as the number of bulbs boost the value of electrical power increases, whilst the worthiness of resistance decreases.

This graph implies that ohms legislation has been obeyed as the current streaming through is quiet proportional to the actual difference across.


There might have been one anomaly that was saved within the series circuits between your 3 and 4 lights experiment as the existing should have decreased but remained the same. However this could have been just because a needle ammeter was used, therefore is subject to one's thoughts and opinions thus not completely accurate, to be able to boost this a digital ammeter could have been used to boost reliability.

Also the ammeter scale couldn't be accurately read as there is no gradation between your 1 and 2 worth.

In order to enhance the method more volume of bulbs could have been used showing more of an overall development which would improve validity and stability of conclusion. In order to improve the consistency and validity of the method a repeat should be conducted of the experiment to attain average results. Overall, the results match theory thus portraying the results achieved are reliable.

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