particle accelerators

An electric field can be used to accelerate charged particles.

Conservation of energy tells us that

work done by the electric field = change in the particle’s kinetic energy

The speed of the particle can be determined if its charge and the accelerating voltage (potential difference) are known.  The notes attached to the end of this post will show how to perform the calculation.

These short video clips show how to draw electric field lines for point charges and parallel plates, with example calculations for the work done by electric fields and the final speed of charged particles in electric fields.

Q1(a) Electric fields lines around point charges from mr mackenzie on Vimeo.

Q1b – Electric field between parallel plates from mr mackenzie on Vimeo.

Q2 – Work done in moving a charged particle through a potential difference from mr mackenzie on Vimeo.

Q3 – Calculating the speed of a charged particle in an electric field from mr mackenzie on Vimeo.

National 5 – Satellites

We’ve started looking at telescopes and this BBC programme from 2 years ago featured the replacement for Hubble, the James Webb Space Telescope.  The presenter, Maggie Aderin Pocock now hosts The Sky at Night on BBC4.

Please take some time to watch both parts of the film.  Maggie covers the basic idea of satellites, how we achieve geostationary orbit, looks at examples of Earth observation and the manufacture of the James Webb’s massive 6.5m mirror.  In part 1, around 17 minutes in, you’ll see satellite footage over the Highlands, can’t quite see Thurso though.

Satellites-part1 from mr mackenzie on Vimeo.

Satellites-part2 from mr mackenzie on Vimeo.

If you want to download a copy of the video to watch later, use the download link below.  Please be patient, the file is about 660MB in size.