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Question 19M.2.HL.TZ1.a.i

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Date May 2019 Marks available [Maximum mark: 3] Reference code 19M.2.HL.TZ1.a.i
Level HL Paper 2 Time zone TZ1
Command term Calculate Question number a.i Adapted from N/A
a.i.
[Maximum mark: 3]
19M.2.HL.TZ1.a.i

A student makes a parallel-plate capacitor of capacitance 68 nF from aluminium foil and plastic film by inserting one sheet of plastic film between two sheets of aluminium foil.

The aluminium foil and the plastic film are 450 mm wide.

The plastic film has a thickness of 55 μm and a permittivity of 2.5 × 10−11 C2 N–1 m–2.

Calculate the total length of aluminium foil that the student will require.

[3]

Markscheme

length =  d × C width × ε ✔

= 0.33 «m» ✔

so 0.66/0.67 «m» «as two lengths required» ✔

Examiners report

Many candidates were able to use the proper equation to calculate the length of one piece of aluminum foil for the first two marks, but very few doubled the length for the final mark.

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