Understanding Light through the Wave Model

A comprehensive set of flashcards covering key concepts related to the properties of light and the electromagnetic spectrum.

Who first measured the speed of light?

Albert Michelson

What is the approximate speed of light?

3×10^8 m/s

Why do we see lightning before hearing thunder?

Because light travels faster than sound.

Which device does NOT primarily use light: Microscope, Binoculars, Periscope, or Stethoscope?

Stethoscope.

What explains the ‘bent stick’ effect in water?

Refraction.

What kind of reflection happens on a smooth surface?

Specular reflection.

What is the order of visible light colors?

Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).

Which waves are used in remote controls and heat sensors?

Infrared waves.

Which EM wave has the highest energy?

Gamma rays.

What happens to wavelength when frequency increases?

It decreases (inverse relationship).

What did Pythagoras believe about light?

Light is made of tiny particles, and eyes detect them.

How do you estimate how far lightning is?

Count seconds between lightning and thunder, multiply by speed of sound.

What is a light year?

The distance light travels in one year.

Name four technologies that use light.

Microscope, Telescope, Fibre Optics, Laser.

What is visible light?

A form of energy visible to the human eye.

What is rectilinear propagation?

Light travels in straight lines.

What is dispersion?

The separation of white light into colors (e.g. via a prism).

What is amplitude in a wave?

The height of a wave from rest to crest (or depth to trough).

What is the wavelength range of visible light?

390 nm to 780 nm.

Why is overexposure to X-rays dangerous?

X-rays can increase cancer risk and damage cells.

Can light travel through a vacuum?

Yes.

Does sound travel faster than light?

No.

What type of reflection occurs on rough surfaces?

Diffuse reflection.

Are ultraviolet rays visible to the human eye?

No.

Which bends more in a prism: red or violet light?

Violet.

Where do gamma rays come from?

Nuclear reactions and cosmic events.

Does the electromagnetic spectrum only include visible light?

No.

What is microwave radiation used for?

Cooking and telecommunications.

Do higher frequency waves carry more or less energy?

More energy.

Is light a form of kinetic energy?

No, it is electromagnetic energy.

What two variables are inversely related in a light wave?

Wavelength and frequency.

What is the relationship between wave frequency and energy?

Higher frequency = more energy.

What is a wave’s wavelength?

The distance between two consecutive peaks or troughs.

What unit is wave frequency measured in?

Hertz (Hz).

What is the amplitude of a wave?

The height from the rest position to the crest (or depth to trough).

What does amplitude determine in a light wave?

The energy/intensity of the wave.

What is electromagnetic radiation (EMR)?

Energy transmitted in the form of waves.

Name the 7 types of electromagnetic radiation (from longest to shortest wavelength).

Radio, Microwave, Infrared, Visible Light, Ultraviolet, X-rays, Gamma rays.

What is the visible range of the electromagnetic spectrum?

390 nm to 780 nm.

What type of EM wave is used in medical imaging of bones?

X-rays.

What type of EM wave is used in MRIs?

Radio waves.

What does UV radiation do to bacteria?

Kills them.

How does the Earth's atmosphere protect us from harmful EM waves?

It blocks or absorbs many high-energy waves (like UV and gamma rays).

What is refraction?

The bending of light as it passes from one medium to another.

What kind of medium is required for light to travel through space?

None; light can travel through a vacuum.

What does 'rectilinear' mean in terms of light?

Straight-line movement.

Why is violet light bent more than red light in a prism?

Violet has a shorter wavelength and higher frequency.

What is the purpose of fibre optics?

To transmit light for communication or imaging.

What kind of device uses a combination of lenses to magnify small objects?

Microscope.

What kind of wave does not belong to the EM spectrum?

Sound waves.

What happens to light when it enters a new medium at an angle?

It bends (refracts).

Which color of visible light has the lowest energy?

Red.

Which color of visible light has the highest energy?

Violet.

How do lasers use light differently from regular light sources?

They emit focused, coherent, monochromatic beams.