OCR A Level Physics

Topic Questions

6.3 Electric Fields

11 mark

The diagram below shows two uniformly charged spheres separated by a large distance z.

q2-paper-2-june-2019-ocr-a-level-physics

The radius of the small sphere is x and the radius of the large sphere is y.

Which is the correct distance to use when determining the electric force between the charged spheres?

  • z

  • x + z

  • y + z

  • x + y + z

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11 mark

A beam of charged particles is not deflected when it passes through a region where both electric and magnetic fields are present.

Which statement is not correct?

  • All the particles have the same speed.

  • The resultant force on each particle is zero.

  • The magnetic force is equal to the electric force on each particle.

  • The magnetic field and the electric field are in the same direction.

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21 mark

The electric field strength at a distance of 2.0 × 10-8 m from a nucleus is 3.3 × 108 NC–1.

What is the charge on the nucleus?

  • 1.6 × 10-19C

  • 1.5 × 10-17C

  • 7.3 × 10-10C

  • 3.8 × 10-9C

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31 mark

Two isolated parallel capacitor plates have an equal and opposite charge.
The separation between the plates is doubled.
The charge on each plate remains the same but the potential difference between the plates doubles.

q9-paper-2-june-2017-ocr-a-level-physics

Which statement is correct?

  • The capacitance of the capacitor doubles.

  • The energy stored by the capacitor is halved.

  • The permittivity of free space doubles.

  • The electric field strength between the plates remains the same.

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41 mark

An electron is released at a distance r from the surface of a positively charged sphere. It is attracted towards the centre of the sphere and moves until it touches the surface.

q13-paper-2-june-2018-ocr-a-level-physics

Which of the following statements is/are correct?

1
The area under the F against r graph is equal to work done on the electron.

2
The electric field strength E at distance r is equal to fraction numerator F over denominator 1.6 space cross times 10 to the power of negative 19 end exponent end fraction
3
The work done on the electron is equal to F × r.
  • Only 1

  • Only 1 and 2

  • Only 1 and 3

  • 1, 2 and 3

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