Exploring the Structure of Matter (Edexcel International A Level Physics)

In 1931, Sloan and Lawrence built a linear accelerator (linac) with several drift tubes.
They used the linac to accelerate mercury ions up to energies of 1.26 MeV. The behaviour of the particles was non-relativistic.

The kinetic energy of a non-relativistic particle of mass m with momentum p is given by

Derive this formula.

A mercury ion with kinetic energy 6.42 × 10^–15 J leaves a drift tube, as shown.

Calculate the momentum of the mercury ion when it reaches the next drift tube.
   mass of mercury ion = 3.32 × 10^–25 kg
   charge of mercury ion = 1.60 × 10^–19 C
   electric field strength between drift tubes = 7.64 × 10⁶ Vm^–1

   distance between drift tubes = 5.50 × 10^–3 m

Momentum = ........................................

In 1932, Carl Anderson published this photograph of a track in a cloud chamber. The cloud chamber contained a lead plate. There was a magnetic field perpendicular to the plane of the track.

The photograph shows the track of a positron from cosmic rays and is the first photographic record of the existence of an antiparticle.

Deduce the direction of the magnetic field.

In the upper part of the photograph the positron had an energy of 23 MeV.  

(3)

where E = particle energy, p = particle momentum and c = speed of light.

Determine the magnetic flux density of the magnetic field.

radius of curvature of path = 3.7 cm

(3)

Magnetic flux density = .........................................

A positron travelling at a non-relativistic speed of 1.5 × 10⁷ m s⁻¹ collides with an electron travelling at the same speed in the opposite direction. This collision results in the production of gamma radiation.
Calculate the frequency of the gamma radiation produced.

Frequency = ..........................................