DP Physics (first assessment 2025)

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Question 20N.2.HL.TZ0.8a

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Date November 2020 Marks available [Maximum mark: 2] Reference code 20N.2.HL.TZ0.8a
Level HL Paper 2 Time zone TZ0
Command term Explain Question number a Adapted from N/A
a.
[Maximum mark: 2]
20N.2.HL.TZ0.8a
(a)

Explain why the electric potential decreases from A to B.

[2]

Markscheme

ALTERNATIVE 1
work done on moving a positive test charge in any outward direction is negative ✓
potential difference is proportional to this work «so V decreases from A to B» ✓

 

ALTERNATIVE 2
potential gradient is directed opposite to the field so inwards ✓
the gradient indicates the direction of increase of V «hence V increases towards the centre/decreases from A to B» ✓

 

ALTERNATIVE 3
V=kQR so as r increases V decreases ✓
V is positive as Q is positive ✓

 

ALTERNATIVE 4
the work done per unit charge in bringing a positive charge from infinity ✓
to point B is less than point A ✓

Examiners report

The majority who answered in terms of potential gained one mark. Often the answers were in terms of work done rather than work done per unit charge or missed the fact that the potential is positive.

Syllabus sections