Edexcel A-Level Physics Uniform Electric Fields

Practise Edexcel A-Level Physics uniform electric fields between plates by using voltage, separation and force on charges.

Exam points

use E equals V over d to find plate separation, potential difference or field strength
combine uniform field strength with electric force to analyse charged oil drops
predict electron deflection changes from plate voltage, separation or field direction

[Maximum number: 3]

A spark chamber consists of a set of parallel metal plates. It can reveal the path of a high energy particle as shown.

Figure for Question 4.4.97 - Uniform electric field between plates question 1 — Edexcel A-Level Physics A2

A potential difference of 10.5 kV is applied across two adjacent plates as shown below.

A high energy particle causes ionisation of the atoms in the space between the plates.

Show that the force on an ionised atom due to the electric field is
about $2.6 \times 10^{-13} \mathrm{~N}$ .
charge on ionised atom $=1.60 \times 10^{-19} \mathrm{C}$
distance between plates $=6.40 \mathrm{~mm}$

Use E=V/d and F=EQ. Hence $F=(10500/0.00640)(1.60\times10^{-19})=2.63\times10^{-13}\,\mathrm{N}$ , about $2.6\times10^{-13}\,\mathrm{N}$ .

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4.4.97 - Uniform electric field between plates question 1