Equations Flashcards
Equation for current
I=Q/t
Equations for voltage?
V=w/Q
V=IR
Resistance of a parallel circuit?
1/resistancet =1/R1 +1/R2….
Equation for energy transferred?
E=QV
P=IV
Equation for power and then power loss?
P=IV
P=I^2R
Transformer equation for 100% efficient
VpIp=VsIs
Transformer equation
Vs/Vp=Ns/Np
Equation for annihilation reaction?
E=mc^2
Equation for heart rate?
1/time period (for one beat) x 60
What is peak frequency?
Hot objects always emit more of onevfrequency than any other this wavelength is called the peak frequency
The higher the temperature the more radiation it emits so higher peak frequency
What does a hot star look like?
Blue due to high frequency
How do you work out what stars are made of?
Use spectra as each element has its own line spectrum, compare it to stars spectra and compare positions
Evidence for red shift?
Spectra of distant galaxy is shifted to left compared to earths so shows moving away
Distance time graphs
Gradient
Negative gradient
Curves
Velocity
Going back
Acceleration/deceleration
What is acceleration?
Change in velocity -speed or direction
Equation for Acceleration
Change in velocity / change in time
Velocity time graph
Gradient
Area
Curve
Acceleration
Distance travelled
Changing acceleration
Equation for weight
W=mg
What does a resultant force mean
Object will change urs state of rest or motion
Change in velocity - object will accelerate in its direction
Force equation
F=ma
Equation for momentum
Momentum=mv
Momentum before=
Momentum after collision
Equation for force
F=change in momentum/ time
Work done equation
E=Fd
What is power and it’s equation?
Rate of doing work
Power=w/t=energy transferred/ time
What is power measured in?
J/s
Equation for kinetic energy?
Kinetic energy=0.5x mass x velocity^2
Kinetic energy liked to work done by brakes?
0.5mv^2=Fd
Equation for gravitonal potential energy
Gravpot=mgh
What do falling objects do?
Concert GPE to KE
4 car adaptations
Crumple zones
Air bags
Seat belts
Side impact bar
2 examples of transverse waves?
Light/ EM waves
S- waves seismic
Examples of longitudinal waves?
Sound waves
P-waves (seismic)
Equation for speed of a wave?
S=f x wavelength
What feature of a wave doesn’t change once it’s left the source?
Frequency
What is the law of reflection
Angle of incidence=angle of reflection
What is the range of human hearing?
20kHz
Speed of em wave in a vacuum?
3x10^8
Order of Em from largest wave length
Radio Micro Infrared Visible Ultra violet X-ray Gamma
Radio waves
Communication
Long wave=diffract around earths surface
Diffract around hills etc
Short wave- radio and tv
Travel long as reflected off ionosphere
Microwaves
Satellites and mobile phones
-pass through atmosphere
Microwave ovens
Infrared
Monitoring temperatures
Cooking
Wireless controls
Optical fibres
Visible light
Photography
Optical fibres
Ultra violet
Detect forged bank notes
Skin cancer , cataracts, pre skin aging
Which waves can cause ionisation?
Ultra violet, X-ray, gamma ray
X-rays
Radiography imaging
Gamma rays
Cancer treatment
Which way does energy flow?
From hot to cold
What is temperature?
Measure of the average kinetic energy of particles
Why doesn’t temp go down until all liquid/solid?
When condensing or freezing bonds are formed between particles which releases energy
What is conduction Of heat?
Where vibrating particles pass on extra kinetic energy to neighbouring particles
Equation for density?
D=m/v
What is the third gas law?
Pressure is directly proportional to temperature when the volume is constant
