Physics 4 - Waves electromagnetism, and space (P12 - P16) Flashcards
What do Transverse Waves do? Give an example.
Oscillate perpendicular to the direction of energy transfer of the waves. All electromagnetic waves are Transverse.
What do Longitudinal Waves do? Give an example.
Oscillate parallel to the direction of energy transfer of the waves. Sound waves are longitudinal.
What do Mechanical waves do?
They need a substance to travel through. They can be transverse or longitudinal.
What is the equation for wave speed?
Wave speed (m/s) = Frequency (Hertz Hz) x Wavelength λ (metres m)
What element of waves effects the pitch of soundwaves?
Frequency.
What happens to soundwaves if amplitude is increased?
The volume increases.
What is the equation for distance travelled by a wave?
Distance travelled (m) = speed of ultrasound waves in body tissue (m/s) x time taken (seconds)
What is the equation for the depth of the boundary below the surface that a wave penetrates?
The depth of the boundary below the surface (m) = 0.5 x speed of the ultrasound waves (m/s) x time taken (seconds)
What are ultrasound waves?
Sound waves with a frequency above the range of human hearing.
What are seismic waves?
Waves that travel through the earth’s crust.
Which end of the electromagnetic spectrum has the longest wavelength?
Radio waves (The beginning)
What speed do electromagnetic waves travel at?
300 million m/s (Speed of light)
What type of light contains all the colours of the visible spectrum?
White light.
Which side of the visible light spectrum has the longest wavelength?
Red light.
(P14) How do you draw the normal at a point on a mirror?
It is a line drawn perpendicular to the mirror.
What is the law of reflection?
It states that the angle of incidence = the angle of reflection.
What is the angle of incidence?
The angle between the incident ray and the normal
What is the angle of reflection?
The angle between the reflected ray and the normal.
What is specular reflection?
Reflection in a single direction without scattering. Diffuse reflection is reflection from a rough surface that scatters the light.
What is refraction of light?
The change in direction of waves when they travel across boundary from one medium to another.
Which is bigger, the angle of refraction or the angle of incidence when a light ray travels from air to glass?
The angle of incidence.
Which is bigger, the angle of refraction or the angle of incidence when a light ray travels from glass to air?
The angle of refraction.
What does a translucent object do to light rays?
Lets light pass through it but scatter or refracts the light inside it.
What does a transparent object do to light rays?
Lets all the light that enters pass through it and does not scatter or refract the light.
What does a convex lens do to parallel rays?
Focuses them to a point called the principal focus.
What does a concave lens do to parallel rays?
Spreads them out as if they had come from a point called the principal focus.
How is a real image formed by a convex lens?
If the object is further away than the principal focus.
How is a virtual image formed by a convex lens?
If the object is closer than the principal focus.
What is the equation for magnification?
Magnification = image height / object height
What is a ray diagram used for?
To find the position and nature of an image formed by a lens.
What is the nature of an image formed when an object is placed between a convex lens and its principal focus? (four things)
The image formed is virtual, upright, magnified and on the same side of the lens as the object.
What type of lens does a camera have and what is it used for?
A convex lens that is used to produce a real image of an object.
What type of lens does a magnifying glass have and what is it used for?
A convex lens that is used to form a virtual image of an object.