• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Questions and answers on the 'Photoelectric Effect'.

Extracts from this document...


Physics Assessment Task

Part 1

  1. Explain what is meant by the ‘Photoelectric Effect’.

The Photoelectric effect occurs when light falls onto a metal surface and electrons are emitted. This not only depends on the frequency and intensity of light, but also the metal.

Einstein explained this phenomenon by employing the ‘Particle Theory” of light, claiming that there are photons in light, and these are packets of energy. When atoms of an element are irradiated by a light source, the electrons can absorb energy from these photons and move into a higher energy shell. The light must have a minimum frequency or energy for this process to be exhibited. It was found that if light was at, or above, this certain minimum frequency, then the amount of electrons emitted is proportional to the intensity of light.

Later is was found that each metals has a minimum frequency required to release electrons, it was proved that if the light frequency was below this minimum value no electrons would be ejected, no matter how intense the light was. When the frequency was above the minimum electrons would be released and the more intense the light or the more photons the more electrons that were emitted. Also higher frequency EMR displayed this effect the best.

...read more.


Solar energy is a cost-effective and viable option in many remote areas where power companies may charge anywhere from $18,000-$60,000 a kilometre (depending on terrain) to run a power line to an ‘unserviced’ area.

Though solar energy has its limitations

Not all light is used in this process, most of the sunlight energy cannot be used to free electrons in the solar cells, as it is the wrong frequency and either is reflected or passes through without hitting the electrons.

The electricity attained has a very small electrical potential, even with the most efficient solar cells, therefore they must be chained together in large arrays to be effective enough to provide sufficient energy.

It can only be used during sunny days, it is not suitable for cloudy climates and start up costs are uneconomical.

At the moment solar energy supplies less than 1% of the worlds energy.

Then the most obvious question. What happens when the sun is not shinning?

Though they need to be able to compete with utilities, research is still going on to bring the price of these down though it wont happen for a while yet.

Part of the problem is that manufacturing needs to be done on a large scale to reduce costs as much as possible.

...read more.


Despite all this there has been tests in Denmark of Superconductor transmission lines, and there are plans for the future. In May of 2001 150,000 residents of Copenhagen, Denmark, received their electricity through HTS (high-temperature superconducting) material. That cable was only 30 meters long, but proved adequate for testing purposes.

More efficient electrical generators can be manufactured if superconducting wire is used rather than the conventional copper wire. If superconducting wire was made into loops, when large currents flow a powerful electromagnet would be set up that would be very effective in a motor or generator as long as it stays below its critical temperature. The efficiently would be well above 99% and their size would half that of normal generators.

Electronic Switches

Fast computers rely of switching between current highways using transistors made from semiconductors. Superconducting devices can be designed to pass a fixed current with barley any driving voltage. The idea is to manufacture computers that are up to 200 times faster than conventional high-speed computers.

The problem of cooling these devices to their critical temperature still exist, and higher temperature superconductors need to be found that are more suited to their applications. The ideal superconductor would need to be ductile, have a critical temperature much higher than the current and arechemically stable in a variety of environments.

...read more.

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Electricity and Magnetism essays

  1. The Efficiency of an Electric Motor.

    B=field strength, L=length of coil perpendicular to the magnetic field, and I=the current). If you look at my results you can see that the current is small for small loads. When the current is small the work done against friction is the term in which most energy is wasted.

  2. Electromagnetism - investigating what effect increasing the number of turns in a coil on ...

    * I will have to use the same method of measuring the magnetic force of the magnet I have decided to use ten-gram weights because weights would give me an answer in grams straight away; a Newton meter would give an answer in Newton's.

  1. Choosing a light source

    Mostly halogen light bulbs contain iodine of bromine. When the tungsten evaporates from the surface at high temperatures, it combines with the halogen gases. For the tungsten to stay combined with the halogen gases, the temperature of the surrounding must be 200OC.

  2. A hydrogen Vehicle

    Conversely hydrogen cars cannot be charged at home like electric cars. Electric cars can be charged essentially anywhere the electric grid extends, including, most importantly, a car-owner's home. This contrasts very sharply with hydrogen cars that will only be chargeable where special hydrogen fuelling stations are built, and none are yet constructed.

  1. Efficiency of a Motor

    The formula for this is: Mass � g � change in height G is gravity. We measure this as 10N. The total energy input is the power put into the motor. We calculate this using the formula: Voltage � current � time This means that to find the energy efficiency

  2. Chessington World of Adventure.

    This means the total momentum before collision is equal to the total momentum after collision. There are two types of collision- elastic and inelastic collision. Elastic collision- This is collision in which kinetic energy and momentum are conserved. E.g the collision of molecules of gas in a container.

  1. Investigation on Photovoltaic Cells

    is different ways of making renewable energy instead of burning fossil fuels. Only recently has the photovoltaic industry become high in demand. Therefore for my science investigation I have decided to study solar cells and how the surface area affects the amount of electricity produced.

  2. Investigating Bubble Wrap as an Insulator

    Finally, this cooler air now replaces the air which is rising. This is the how heat energy moves in convection. Radiation is the transferring of heat energy by waves with no particles being involved. Hot objects send out mainly infrared radiation, and the hotter the object, the energy it radiates.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work