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Subjects · Leaving Cert Physics & Chemistry

Leaving Cert Physics & Chemistry: Mirrors & lenses

How often Mirrors & lenses comes up on the Physics & Chemistry papers, every year it was asked, and questions to try.

HL Asked on 9 of the last 9 Higher Level papers, most recently in 2025. banker

OL Asked on 9 of the last 9 Ordinary Level papers, most recently in 2025. banker

Mirrors & lenses, Higher Level(7 marks)

Quick ones on Mirrors & lenses.

(a)Laws of reflection: angle i = angle r, and the incident ray, reflected ray and normal…
  1. All meet at the focus
  2. All lie in the same plane
  3. Are all parallel
(b)A concave mirror has a radius of curvature of 30 cm. Its focal length?
  1. 30 cm
  2. 60 cm
  3. 15 cm
(c)An object is 15 cm from a converging lens of focal length 10 cm. Image distance?
  1. 30 cm
  2. 25 cm
  3. 6 cm
Show the answers

(a) All lie in the same plane

(b) 15 cm

(c) 30 cm

Your turn: Higher Level questions on Mirrors & lenses.

Higher Level

Asked on 9 of the last 9 Higher Level papers, most recently in 2025. banker

Every paper, year by year

YearWhere it came up
2025Q1(e), Q1(f), Q3
2024Q3
2023Q1(h), Q4
2022Q1(j), Q3
2021Q3
2019Q1(e), Q1(f)
2018Q3
2017Q3
2016Q1(e), Q3

Links open the State Examinations Commission’s paper for that year.

More Mirrors & lenses questions

Mirrors & lenses, 2 marks

The image formed by a diverging (concave) lens is always…

  1. Real and inverted
  2. Virtual, upright and magnified
  3. Virtual, upright and diminished
Show the answer

Virtual, upright and diminished

A diverging lens spreads rays out, so they never meet. The image is found by tracing them back: virtual, upright, smaller, on the same side as the object.

Mirrors & lenses, 3 marks

An object is 40 cm from a concave mirror of focal length 20 cm. Image distance?

  1. 13.3 cm
  2. 40 cm
  3. 20 cm
Show the answer

40 cm

1/v = 1/f − 1/u = 1/20 − 1/40 = 1/40, so v = 40 cm. An object at 2f gives a real, inverted, same-size image at 2f. 13.3 adds the fractions.

Ordinary Level

Asked on 9 of the last 9 Ordinary Level papers, most recently in 2025. banker

Every paper, year by year

YearWhere it came up
2025Q1(h), Q3
2024Q1(h), Q1(i), Q1(j), Q3
2023Q1(i), Q3
2022Q1(f), Q3
2021Q1(h), Q3
2019Q1(f), Q3
2018Q1(f), Q3
2017Q3
2016Q1(e), Q3

Links open the State Examinations Commission’s paper for that year.

More Mirrors & lenses questions

Mirrors & lenses, 2 marks

Laws of reflection: the angle of incidence equals?

  1. The angle of refraction
  2. Twice the angle of reflection
  3. The angle of reflection
Show the answer

The angle of reflection

Both angles are measured from the normal. The second law: the incident ray, reflected ray and normal all lie in the same plane.

Mirrors & lenses, 2 marks

The image in a plane mirror is?

  1. Virtual, inverted and smaller
  2. Virtual, upright and the same size
  3. Real, inverted and the same size
Show the answer

Virtual, upright and the same size

It cannot be caught on a screen (virtual). It is as far behind the mirror as the object is in front, and laterally inverted (left and right swap).

Mirrors & lenses, 2 marks

Which mirror gives a magnified, upright image of a face held close to it?

  1. Concave
  2. Convex
  3. Plane
Show the answer

Concave

With the object inside its focal point, a concave mirror gives a large, upright, virtual image. That is why make-up and shaving mirrors are concave.

Other Physics & Chemistry topics

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