GCSE Physics Quiz: Learn About Lasers and Optical Fibres

Physics Quiz - Light - Other Applications of Light (Questions)

Light has many clever uses in GCSE Physics, from fibre-optic communication to medical scanners. This quiz explores important applications of light in modern technology.

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Fascinating Fact:

Lasers produce narrow, intense beams of light at a single wavelength, which makes them useful for cutting, welding, and precision surgery.

In GCSE Physics, you discover how light can be reflected, refracted and totally internally reflected to carry signals, scan our bodies and read information in devices such as scanners and optical fibres.

Key Terms

Optical fibre: A thin glass or plastic fibre that carries light signals using total internal reflection.
Total internal reflection: When light is completely reflected inside a medium instead of passing out into the next medium.
Coherent light: Light waves that have the same wavelength and stay in step, as in a laser beam.

Frequently Asked Questions (Click to see answers)

What are common applications of light in GCSE Physics?

In GCSE Physics, you meet applications of light in optical fibres for communication, bar code scanners, medical imaging, security systems, CD and DVD players, and laser-based measuring equipment.

How do optical fibres work in GCSE Physics?

Optical fibres work by guiding light along a narrow core using total internal reflection. The light repeatedly reflects inside the fibre, so signals can travel long distances with little loss of energy.

What is a laser and why is it useful in technology?

A laser is a source of coherent, single-wavelength light that can be focused into a very small spot. This makes it useful in medicine, industry, communication links and precise measuring instruments.

Try These Related Quizzes

Which of the following is NOT an application of total internal reflection?

[ ]	Endoscopes
[ ]	Fibre Optic Broadband
[ ]	Telescopes
[ ]	Tacky Christmas Decorations!

What is the definition for critical angle in optics?

[ ]	The angle below which total internal reflection occurs
[ ]	The critical angle is the angle of incidence above which total internal reflection occurs
[ ]	The angle between the normal and the angle of incidence
[ ]	The angle between the normal and the angle of refraction

Optical fibres can be used to transmit which of the following?

[ ]	Light
[ ]	Electrons
[ ]	Protons
[ ]	All of the above

Which of the following are examples of optical fibres?

[ ]	Endoscope
[ ]	Digital audio optical connection
[ ]	Telephone exchange coupling
[ ]	All of the above

What is a laser?

[ ]	A device that generates an intense beam of coherent monochromatic light
[ ]	A device that generates an intense beam of coherent bi-chromatic light
[ ]	A device that absorbs an intense beam of coherent monochromatic light
[ ]	A device that absorbs an intense beam of coherent bi-chromatic light

Lasers can be used for a variety of applications. Which of the following are lasers useful for?

[ ]	Cutting
[ ]	Cauterising
[ ]	Burning
[ ]	All of the above

Which formula correctly states the relationship between refractive index and critical angle?

[ ]	refractive index = ¹⁄_{sin c}
[ ]	refractive index = ²⁄_{sin c}
[ ]	refractive index = ¹⁄_{2 sin c}
[ ]	refractive index = ²⁄_{3 sin c}

Calculate the refractive index of a medium which has a critical angle of 52^o.

[ ]	1.15
[ ]	1.27
[ ]	1.32
[ ]	1.44

What is the critical angle of a medium if its refractive index is 1.5?

[ ]	40^o
[ ]	41.8^o
[ ]	50^o
[ ]	51.8^o

10.

What is the normal range of sight for a human eye?

[ ]	25 cm to infinity
[ ]	5 cm to infinity
[ ]	10 cm to infinity and beyond
[ ]	25 cm to about 1 m

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

Physics Quiz - Light - Other Applications of Light (Answers)

Which of the following is NOT an application of total internal reflection?

[ ]	Endoscopes
[ ]	Fibre Optic Broadband
[x]	Telescopes
[ ]	Tacky Christmas Decorations!

Telescopes rely on light passing through a series of lenses or reflection off a curved mirror to bring it to a focus

What is the definition for critical angle in optics?

[ ]	The angle below which total internal reflection occurs
[x]	The critical angle is the angle of incidence above which total internal reflection occurs
[ ]	The angle between the normal and the angle of incidence
[ ]	The angle between the normal and the angle of refraction

Total internal reflection is the reason that glass fibres can be used to transmit light efficiently from one place to another

Optical fibres can be used to transmit which of the following?

[x]	Light
[ ]	Electrons
[ ]	Protons
[ ]	All of the above

An optical fibre is a bundle of glass fibres of high quality. Optical fibres are very flexible

Which of the following are examples of optical fibres?

[ ]	Endoscope
[ ]	Digital audio optical connection
[ ]	Telephone exchange coupling
[x]	All of the above

Optical fibres have found their way into most parts of our modern day lifestyles now. They are preferred to more conventional methods as they are more efficient and can be made smaller and more cheaply

What is a laser?

[x]	A device that generates an intense beam of coherent monochromatic light
[ ]	A device that generates an intense beam of coherent bi-chromatic light
[ ]	A device that absorbs an intense beam of coherent monochromatic light
[ ]	A device that absorbs an intense beam of coherent bi-chromatic light

Coherent means that all the lightwaves are 'in phase' (all their crests and troughs are lined up). Monochromatic means that the light waves in a laser beam all have the same wavelength

Lasers can be used for a variety of applications. Which of the following are lasers useful for?

[ ]	Cutting
[ ]	Cauterising
[ ]	Burning
[x]	All of the above

The strength of the laser should be considered when dealing with each situation, as some may require stronger lasers than others

Which formula correctly states the relationship between refractive index and critical angle?

[x]	refractive index = ¹⁄_{sin c}
[ ]	refractive index = ²⁄_{sin c}
[ ]	refractive index = ¹⁄_{2 sin c}
[ ]	refractive index = ²⁄_{3 sin c}

Different transparent media have different refractive indices

Calculate the refractive index of a medium which has a critical angle of 52^o.

[ ]	1.15
[x]	1.27
[ ]	1.32
[ ]	1.44

sin c = 0.788, 1/0.788 = 1.27. Refractive index has no units and is always quoted as just a number