GCSE Physics Lenses Quiz Test Your Knowledge of Refraction

Physics Quiz - Light - Lenses 02 (Questions)

In GCSE Physics you learn how lenses bend light, form images and help us focus. This quiz checks your skills with ray diagrams and lens rules.

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Fascinating Fact:

Ray diagrams for lenses usually show three key rays: one through the centre, one parallel to the axis, and one through the focus, to locate the image.

In GCSE Physics, you learn how converging and diverging lenses bend light, form real and virtual images, and help us design devices such as cameras, magnifying glasses and corrective spectacles.

Key Terms

Principal axis: The straight line that passes through the centre of a lens and its focal points.
Focal length: The distance from the centre of a lens to its principal focus.
Real image: An image formed where light rays actually meet and can be projected onto a screen.

Frequently Asked Questions (Click to see answers)

How do I draw a ray diagram for a convex lens in GCSE Physics?

To draw a convex lens ray diagram, use a ray parallel to the principal axis through the focus, a ray through the centre of the lens, and a third ray if needed. Their intersection shows the image position.

What is the difference between converging and diverging lenses?

A converging lens (convex) brings parallel rays together at a focus and can form real images. A diverging lens (concave) spreads rays apart and forms only virtual images that cannot be projected onto a screen.

Why do we learn lens ray diagrams for GCSE Physics exams?

Lens ray diagrams are tested at GCSE because they help you predict image position, size and type. Understanding them supports questions on cameras, the eye, spectacles and optical instruments in the exam.

Try These Related Quizzes

A lens which focuses light to a point is called a what?

[ ]	A converging lens
[ ]	A diverging lens
[ ]	A meniscus lens
[ ]	A biconvex lens

What is the unit of power for a lens?

[ ]	Watt
[ ]	Joule
[ ]	Dioptre
[ ]	Metre

What is the power of a lens dependent on?

[ ]	The type of wave incident on the lens
[ ]	The focal length of the lens
[ ]	The time of day
[ ]	The way the lens is being held

The power of a lens (SI system) can be calculated using which of the following formulae?

[ ]	Power = 1 / focal length (in m)
[ ]	Power = focal length / 1
[ ]	Power = 1 / focal length (in cm)
[ ]	Focal length (m) = 1 / Power²

What is chromatic aberration?

[ ]	Where light is split into constituent colours as it travels through a lens
[ ]	Separate rays of coloured light are converged into one beam of chromatic light
[ ]	Where chromatic light is split into two colours after travelling through a lens
[ ]	Chromatic aberration does not affect light

In the eye, which of the following parts does light NOT travel through?

[ ]	The pupil
[ ]	The lens
[ ]	The cornea
[ ]	The iris

What is the power of lens which has a focal point of 20 cm?

[ ]	0.05
[ ]	0.5
[ ]	5
[ ]	50

What is the focal length of a lens which has a power of 0.5?

[ ]	2 cm
[ ]	2 m
[ ]	0.2 m
[ ]	0.5 m

What part of the eye focuses the light?

[ ]	The lens
[ ]	The iris
[ ]	Suspensory ligament
[ ]	Retina

10.

Calculate the power of a converging lens of focal length 0.05 m.

[ ]	20
[ ]	-20
[ ]	-2
[ ]	2

You can find more about this topic by visiting BBC Bitesize - Lenses

Physics Quiz - Light - Lenses 02 (Answers)

A lens which focuses light to a point is called a what?

[x]	A converging lens
[ ]	A diverging lens
[ ]	A meniscus lens
[ ]	A biconvex lens

Converging means coming together

What is the unit of power for a lens?

[ ]	Watt
[ ]	Joule
[x]	Dioptre
[ ]	Metre

The higher the number of dioptres, the more a lens will bend light rays

What is the power of a lens dependent on?

[ ]	The type of wave incident on the lens
[x]	The focal length of the lens
[ ]	The time of day
[ ]	The way the lens is being held

The focal length depends on the curvature of the lens and the material from which it is made

The power of a lens (SI system) can be calculated using which of the following formulae?

[x]	Power = 1 / focal length (in m)
[ ]	Power = focal length / 1
[ ]	Power = 1 / focal length (in cm)
[ ]	Focal length (m) = 1 / Power²

Remember to convert focal length to metres

What is chromatic aberration?

[x]	Where light is split into constituent colours as it travels through a lens
[ ]	Separate rays of coloured light are converged into one beam of chromatic light
[ ]	Where chromatic light is split into two colours after travelling through a lens
[ ]	Chromatic aberration does not affect light

It decreases the quality of the image

In the eye, which of the following parts does light NOT travel through?

[ ]	The pupil
[ ]	The lens
[ ]	The cornea
[x]	The iris

The iris is the coloured part of the eye which controls the size of the pupil. So allowing more or less light to enter the eye depending on the conditions

What is the power of lens which has a focal point of 20 cm?

[ ]	0.05
[ ]	0.5
[x]	5
[ ]	50

Remember that focal length needs to be changed into metres

What is the focal length of a lens which has a power of 0.5?

[ ]	2 cm
[x]	2 m
[ ]	0.2 m
[ ]	0.5 m

This needs you to rearrange the lens power equation