Physics 9702 · AS & A Level · Potential difference and power

Potential difference and power — practice question

(a)[1]

Define electric field strength in terms of force per unit charge.

(b(i))[2]

A uniform electric field is created by a potential difference of $1200\,\text{V}$ across two parallel metal plates in a vacuum, as shown in Fig. 4.1. The gap between the plates is $14\,\text{mm}$. A particle P with charge $3.2 \times 10^{-19}\,\text{C}$ and mass $6.6 \times 10^{-27}\,\text{kg}$ starts from rest at the lower plate and is moved vertically to the upper plate by the electric field. Calculate the electric field strength between the plates.

(b(ii))[2]

Calculate the work done on P by the electric field.

(b(iii))[2]

Calculate the gain in gravitational potential energy of P.

(b)

A uniform electric field is created by a potential difference of $1200\,\text{V}$ across two parallel metal plates in a vacuum, as shown in Fig. 4.1. The separation of the plates is $14\,\text{mm}$. A particle $P$ with charge $3.2 \times 10^{-19}\,\text{C}$ and mass $6.6 \times 10^{-27}\,\text{kg}$ starts from rest at the lower plate and is moved vertically to the upper plate by the electric field. Calculate:

(b(iv))[1]

the increase in kinetic energy of $P$.

(b(v))[2]

the speed of $P$ when it reaches the upper plate.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Electric field strength means the force per unit positive charge acting on a stationary charge

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