physics Flashcards
Do you always need units in physics answers
yes
weight:
Force of gravity
what is an advantage of an oil power station
It is more reliable, not dependent on weather
weight equation
w=mg
Weight = mass x gravity
pressure equation
P = F/A Pressure = force/area
density equation
P = m/v
Density equals mass/volume
describe the movement of molecules in a solid
Molecules vibrate
describe the movement of molecules in a gas
Molecules move freely, randomly, high speed, zig zag
explain in terms of momentum how the molecules exert a pressure on the walls of the box
Molecules collide with walls
molecules change momentum
Force = change in momentum/time
what is meant by thermometer range
Difference between maximum and minimum temps it can measure
what is meant by thermometer sensitivity
Distance moved by liquid thread per degrees Celsius
how to calculate tension
Mass x gravity
mass equation
Mass = volume x density
the two types of waves
Transverse or longitudinal
what is a Transverse wave
a wave in which the medium vibrates at right angles to the direction of its propagation
what is a longitudinal wave
a wave vibrating in the direction of propagation
Image in a plane mirror
Same size
Upright
virtual image
What is refraction
When the waves go from one medium to another
eg. A ruler in a water tank
Acceleration equation
acceleration = velocity/time
A = vel/time
centripetal
Towards the surface
3 types of acceleration
positive
negative
Centripetal
what is refraction
The bending of light, sound, water and waves. As it passes from one transparent substance into another.
What does refraction make possible
Lenses, magnifying glasses, prisms and rainbows.
without refraction, we wouldn’t be able to focus light on our retina
critical angle abréviation
c
Total internal reflection
More dense -> less dense
angle of incidence > critical angle
what happens when white light enters a prism
It splits into a rainbow
what is another name for a focal point
Principal focus
the centre of the lens is called
optical centre `
The line though the centre of the lens and perpendicular to the lens is called
The principal axis
equation for the magnifications produced by the lens:
M = image height/object height
When does light change direction?
when it enters a lens
What temperature does ice melt at
0 degrees celsius
What is Lf
specific latent heat of fusion
What is Lv
Specific latent heat of vaporisation
Equation for energy required to change substance property
Energy = mass x latent heat H = m L
What wave has the highest frequency out of these three: Ultraviolet, radio waves, infrared waves
Ultraviolet has a higher frequency than radio waves and infrared waves
What wave has the longest wavelength out of these three: microwaves, xrays, gamma rays
Microwaves have a longer wavelength than X-rays and gamma rays
What type of wave is used in satellite communication
Microwaves are used in satellite communication
properties of electromagnetic waves:
Transverse waves
do not need a medium (can travel through a vacuum)
All electromagnetic waves travel with the same high speed of c=3.0x10 to the power of 8 in a vacuum and approximately the same speed in air
As wavelength decreases, frequency must ____
increase
The higher the frequency of an EM wave the greater its ______
energy
Wave equation
Velocity = frequency x wavelength
What type of wave is sound
longitudal
is measuring the size of earthquakes a use of ultrasound
no
Which seismic waves are transverse waves
S-waves
Specific heat capacity
The amount of energy required to raise the temperature of 1kg of a substance by 1 degrees celsius
How many joules are in a mega joule
1000000
1 million
Change in thermal energy =
mass x specific heat capacity x temperature change
ΔE = mc ΔT
Heat capacity for water, ice, steam, aluminium, iron, glass, copper, mercury, gold (J/kg)
Water = 4186 Ice = 2090 Steam = 2010 Aluminium = 900 iron = 448 Glass = 837 Copper = 387 Mercury = 138 Gold = 129
