Wave basics
What is the highest point in a wave called?
What is the distance between two crests called?
Wavelength
What type of wave is visible light?
An electromagnetic wave.
Name two types of electromagnetic waves other than visible light.
Examples: X-rays, microwaves, infrared, ultraviolet, radio waves, gamma rays.
What kind of wave do remote controls use?
Infrared rays
What is a wave defined as?
A disturbance that transfers energy from one place to another.
How does increasing the frequency of a wave affect its energy?
It increases the energy; energy is directly proportional to frequency.
What happens to visible light as it moves from air into water?
It slows down and bends (refraction).
Compare the wavelengths and frequencies of radio waves and gamma rays.
Radio: long wavelength, low frequency. Gamma: short wavelength, high frequency.
Why does thunder follow lightning even though they happen at the same time?
Light travels faster than sound. Light does not need a medium too.
What do we call a wave that needs a medium to travel through?
A mechanical wave.
How do you calculate frequency? What unit is frequency measured in?
Number of oscillations (repeated motions) per second. Hz
Which colour has the most energy?
violet
Why are gamma rays dangerous to living cells?
Gamma rays have the shortest wavelength and highest energy that can ionize atoms and damage DNA.
Why do objects underwater look closer than they really are?
Light bends (refracts) when moving from water to air, altering perceived position.
What are two main types of waves based on the direction of motion? Describe the movements using specific language.
In transverse waves, the medium's particles vibrate perpendicular to the wave's direction of travel, while in longitudinal (compression) waves, the particles vibrate parallel to the wave's direction of travel
If a wave has high frequency, does it have a short or long wavelength?
Short wavelength.
What would happen if you shone only green light on a red object?
The object would appear black—it reflects red and absorbs green.
How are EM waves used in communication satellites?
They transmit data using radio and microwave frequencies between satellites and Earth.
Explain how night-vision goggles use the EM spectrum to “see” in the dark.
They detect infrared radiation (heat) emitted by objects and convert it into visible images.
What is the difference between a mechanical wave and an electromagnetic wave?
Mechanical waves need a medium; electromagnetic waves do not.
What happens to wave speed when a wave enters a new medium at an angle?
It refracts—its speed and direction change.
What happens when white light passes through a prism?
It separates into the visible spectrum of colours (dispersion).
Why can’t humans see most of the electromagnetic spectrum?
Our eyes can only detect visible light wavelengths.
Explain MRIs vs X rays - both are used in medicine, what is the difference in the waves and the images produced?
MRIs (Magnetic Resonance Imaging) uses radio waves to create images, it is used mainly for seeing tissues (brain, muscle, ligaments, organs) and does not use ionizing radiation - safer to use.
X rays - use X rays to take images and can penetrate through bone better. Ionizing radiation