Table of Contents
Title Page1
Introduction3
Research Questions4
Questions4
Answers4
Experiment6

Introduction

This experiment is carried out to show how the

Research Questions

Questions

1) Provide the units used to measure the following quantities, electric current, inductance, frequency, power and energy (work).

2) What is the difference between AC and DC voltages? Give examples.

3) Provided a household has:
* 10 light bulbs of 60 watts each (used 6h/day on average) * TV using 100 watts (used 4h/day on average)
* A washing machine using 1000 watts (used for 3 /h once every 3 days) Calculate the total average energy consumption of this household in a quarter (90 days) in joules than in Kilowatt hours (kWh).

4) If the energy consumption is charged at 20p/kWh, what is the cost of the electricity bill for that quarter?

Answers

1) The following quantities are measured in the following units; - Electric Current is measured in Ampere, A.
- Inductance is measured in Henry, H.
- Frequency is measured in Hertz, Hz.
- Power is measured in Watts, W.
- Energy (work) is measured in Joules, J.

2) AC

3) Power = Energy / Time, therefore Energy = Power x Time. i) 10 bulbs x 60 Watts = 600 Watts, 600 Watts x 6 Hours = 3600 Wh = 3.6 kWh per day. ii) 100 Watts x 4 Hours = 400 Watts = 0.4 kWh per day.

iii) 1000 Watts x 3 Hours = 3000 Wh every 3 days = 1 kWh per day. iv) 1 kWh + 0.4 kWh + 3.6 kWh = 5 kWh per day.
v) 5 kWh x 90 Days = 450 kWh per quarter (90 days).
vi) Using 1 Joule/sec = 1 watt, 1 Joule = 1 Watt x sec, 1k/w = 1000 Watts & 3600 sec in 1 Hour; 450 kWh x 3600 x 1000 = 1620000000 = 1.62 x 10^9 Joules.

4) If electricity bill is 20p/kWh then 450 x 20p = £90.00 for the quarter.

...electric fire element. This wire has much more resistance. Energy has to be spent to force electrons through it. And heat comes off as a result.
All conductors have some resistance but:
 Long wires have more resistance than the short wires.
 Thin wires have more resistance than thick wires.
 Nichrome wire has more resistance than copper wire of the same size.
Resistance is calculated using this equation:
VOLTAGE
RESISTANCE =
CURRENT
The unit of resistance is the ohm
Here is an example:
If there is a voltage of 12 volts across this nichrome, then a current of 4 amperes flows through.
So: 12
Resistance = ohms
4
= 3 ohms
If there is a voltage of 12 volts across this piece of nichrome, then a current of 2 amperes flows through.
So: 12
Resistance = ohms
2
= 6 ohms
The higher the resistance, less current flows for each volt across the wire.
Like electric fires, kettles and hairdryers have heating elements made from coils of thin nichrome wire. The wire gives off heat when a current passes through. But that isn't their job. In some circuits , they are used to reduce the current. In radio or TV circuits they keep currents and voltages at the levels needed to make other parts work properly.
In a variable resistors...

...Physics GCSE coursework: Resistance of wire
Aim: To investigate if the length of wire affects its resistance.
Prediction (Hypothesis):
I predict that the longer the wire the higher the resistance, and the shorter the wire the lower the resistance.
Knowledge:
Resistance is that property of electric components that turn electric energy into heat in opposing the passing of an electric current.It can be beneficial, as in electric heaters, or a pest, as in light bulbs, where the heat is produced alongside the light – we want maximum light and minimum heat. Reistance is often unwanted and we try to minimise it since it results in lost energy, which costs money. Lately superconducters have bee in the news a lot. The are very special conductors which have zero resistance when cooled to a very low temperature. Current may flow for months or years with no measurable loss even when the applied voltage which started the current flowing is removed.
There are two equations which determine the amount of current and the power converted into heat in a resistor: V=IR and P=VI respectively, where
V is the voltage in Volts
I is the current in Amps
P is the power in Watts
R is the resistance in Ohms
The reciprocal of the resistance, 1/R, is called the conductance and is expressed in units of reciprocal ohm, called mho.
Some of the...

...measure resistance, voltage, and continuity; while more advanced versions may be able to provide additional data. This tool can be very useful to have around the house, and anyone who plans on doing electrical repairs should most definitely use a multitester for safety reasons. Multitesters can be used with the current off or on in most cases, although using the device with the current on can sometimes result in damage to the device.
Theory
Ammeters are employed formeasuring current in a circuit and connected in series with the circuit. As ammeter is connected in series, the voltage drop across ammeter terminals should be as low as possible. This requires that the resistance of the ammeter should be as low as possible. The current coil of ammeter has low current carrying capacity whereas the current to be measured may be quite high. For this reason a low resistance is connected in parallel to the current coil.
Voltmeters are employed to measure the potential difference across any two points of the circuit these are connected in the parallel to the circuit. The resistance of voltmeter is kept very high by connecting a high resistance in series of the voltmeter with the current coil of the instrument. The actual voltage drop across the current coil of the voltmeter is only a fraction of the total voltage applied across the voltmeter which is to be measured.
An ohmmeter is a...

...meter
in volt. [0.25 V]
(c) A Wheatstone bridge is balanced with all the four resistances equal to 1kΩ each. The bridge supply voltage is
100V. Now one of the resistances is changed to 1010Ω. The output voltage is measured by a voltmeter of infinite
resistance. Calculate the bridge sensitivity. [25V or 0.025 V/Ω]
(d)Each of the following numbers has a uncertainty of one in the last figure. Determine the number of significant
figures in the following: (i) 46.2x3.15, (ii) 46.2x2.15, (iii) 4246.2x3.15, (iv) 62.3+2.73+0.612
[(i)146, (ii)99, (iii)13400, (iv)65.6]
Q2. The power factor and phase angle in a circuit carrying sinusoidal current and voltage are determined by
measurement of current, voltage and power. The voltage is read as 125.0V on a 150 V scale; the current as 3.00A
on a 5A ammeter; the power, 225 watts on a 500W wattmeter. The ammeter and voltmeter are guaranteed to be
accurate within ± 0.5% of the full scale value, and the wattmeter within ±0.25% of full scale.
(a) To what percentage accuracy can you guarantee the power factor obtained from these readings? [0.6 ±1.99%]
(b) For the possible error in (a), show the amount of contribution by each instrument. [30%, 42%, 28%]
(c) What is the possible error in phase angle? [53.13 ± 0.015degree]
Q3. An oscilloscope having an input resistance of 1MΩ shunted by a 50pF capacitance is connected across a circuit
of effective output...

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Resistance
No pain, no palm; no thorns, no throne; no gall, no glory; no cross,
no crown.
—William Penn
Historical Proﬁles
Georg Simon Ohm (1787–1854), a German physicist, in 1826
experimentally determined the most basic law relating voltage and current for a resistor. Ohm’s work was initially denied by critics.
Born of humble beginnings in Erlangen, Bavaria, Ohm threw himself into electrical research. Ohm’s major interest was current electricity, which had recently been advanced by Alessandro Volta’s invention
of the battery. Using the results of his experiments, Ohm was able to
deﬁne the fundamental relationship among voltage, current, and resistance. This resulted in his famous law—Ohm’s law—which will be covered in this chapter. He was awarded the Copley Medal in 1841 by the
Royal Society of London. He was also given the Professor of Physics
chair in 1849 by the University of Munich. To honor him, the unit of
resistance is named the ohm.
Ernst Werner von Siemens (1816–1892) was a German electrical
engineer and industrialist who played an important role in the development of the telegraph.
Siemens was born at Lenthe in Hanover, Germany, the oldest of
four brothers—all of whom were distinguished engineers and industrialists. After attending grammar school at Lübeck, Siemens joined the
Prussian artillery at age 17 for the...

...Practice 1. Name a substance whose resistance almost remains unchanged by increase of temperature. 2. Name two special characteristics of heater coil. 3. A wire of resistance 4 ohms is bent to form a circle. What is the resistance between two diametrically opposite ends? 4. How does the resistance of a conductor change if its temperature is increased? 5. A current of 4A flows in a wire of resistance 60 ohms. Calculate electrical energy consumed in 2 minutes. 6. V-I graph for two resistors is given. Which of the two has minimum resistance? 7. Alloys are used in electrical heating devices rather than pure metals. Give one reason. 8. An electric geyser has the ratings 2000W, 220V marked on it. What should be the minimum rating, in whole number of a fuse wire that may be required for safe use with this geyser? 9. The electrical resistivity of few materials is given below in ohm-meter. Which of these materials can be used for making element of a heating device? A. 6.84 x 10-8 B. 1.60 x 10-8 C. 1.00 x 10-4 D. 2.50 x 1012 E. 4.40 x 10-5 F. 2.30 x 1017
10. Where do we connect a fuse: with live wire or with neutral wire? 11. What is the resistance of an air gap? 12. Name two safety measures commonly used in electric circuits and appliances. 13. Two metallic wires A and B are connected in parallel. Wire A has length l and radius r, wire B has a length 2l and radius 2r. Compute the...

...Batteries, Resistance and Current
“Battery-Resistor”:
Check “show battery” and “show cores”, watch what happens, adjust some variables
1. Why do electrons (blue dots) move? Draw a diagram of the battery, label the flow of electrons. The flow of current (+) is opposite; draw this and note if toward or away from + terminal of the battery.
The blue dots indicating the electrons move because there is a voltage across the battery in which the electrons flow away from the positive terminal of the battery.
2. What does the Ammeter (on the left) measure? How is this shown in the sim?
The ammeter measures the flow of current through the system.
3. What role do the “green dots” in the resistor play in the sim? What do you think they represent? What does this tell you about the effect of resistors in a circuit?
The green dots in the resistor work in the simulation to slow the flow of current through the system. The green dots represent the resistance to current flow. This tells us that in a circuit resistance works to impede the flow of current. The more resistance the slower or less the amount of current that is able to flow through the system at one time. The less resistance the more current is able to flow through the system.
4. Increase the resistance (# green dots). What affect does this have on temperature? WHY?
Increasing the...

...Resistance coursework
Aim: My aim is to find out which factors affect the resistance of wire and how they affect them.
Ohm's Law:
Ohm's law is also relevant to know of Ohm's Law, which states that the current through a metallic conductor (e.g. wire) at a constant temperature is proportional to the potential difference (voltage). Therefore V ¸ I is constant. This means that the resistance of a metallic conductor is constant providing that the temperature also remains constant. Furthermore, the resistance of a metal increases as its temperature increases. This is because at higher temperatures, the particles of the conductor are moving around more quickly, thus increasing the likelihood of collisions with the free electrons.
Resistance is the ratio of Voltage : Current and we calculate it by using the equation R=V/I.
Variables:
 Material of wire: In my experiment I will be using wire, because it has a high resistance. This could be either it has a closer ions or more ions than other metals. For example Copper has a low resistance due to the arrangement of its ions.
 Temperature: A rise in temperature causes ions inside the metal to vibrate more causing electrons to collide into them this builds resistance; therefore the electrons find it harder to get through the wire. The greater the temperature the greater the...