Physics Exam Cheat Sheet

LIGHT Speed of light 3.00 x 10^8 ms-1 Distance of sun from earth 1.49 x 10^11m Speed = distance traveled / time taken Time taken= distance traveled / speed Time = 1.49 x 10^8 ms-1 / 3.00 x 10 ^8ms-1 =0.49 x 10^3 =496.667 =8 minutes 27 seconds Snells law Sini/Sinr = constant HOW TO DETERMINE THE ANGLE OF REFLECTION Air = 1.00 Glass = 1.533 Angle the light ray entered the glass at = 30o Angle of refraction= Sin-1(sin (30) x 1/1.533 HOW TO DETERMINE THE CRITICAL ANGLE n1=1.53 n2=1 Ө2 =90o Critical angle=Sin-1(n2SinӨ2/n1) Critical angle=Sin-1(1Sin90o/1.53) Refractive index=real depth / apparent depth Mag=Hi/Ho Mirror formula = (1/f=1/v +1/u) f is positive for convex lenses and negative for concave ROYGBIV Violet bends most towards the normal Red bends the least in a higher optically dense substance Remember blue bends best red …doesn’t …bend ….good Dispersion Splitting white light into the spectrum (all colors) Modal dispersion The distortion of light pulses due to the diverging path of the rays coming from the source. Material dispersion The spreading of a light pulse due to the dependence of the index of refraction on color; that is, frequency Transverse waves Light Displacement of particles are perpendicular to wave propagation

Longitudinal waves Sound Particle displacement is parallel to wave propagation

Polarization Constructive interference Destructive interference

Nuclearness Half Life Equation = A=Ao2 ^((t)/(t1/1)) A=current amount of substance Ao = original amount of substance t = time of decay ((t)/(t1/1))=half life Doses Absorbed dose - the amount of energy absorbed per kilogram of target material Absorbed dose (Gy) –Energy absorbed / mass Absorbed dose is measured in Gray (Gy) = 1 joule/kg Dose equivalent = Absorbed does + quality factor Quality factor alpha particle 20 neutrons 10 beta particles 1 gamma rays 1 x rays 1 glossary Fuel rods (U-235) full of fissile material fission occurs in these fuel rods releasing the nuclear energy Control rods (Cadmium boron) raised and lowered to control how many nuclei are being split every second Moderator (water, deuterium) slows down neutrons to be absorbed by U-235 which absorbs slow moving neutrons more easily Coolent (water, high pressure CO2) keeps the temperature constant Containment vessel (steel & concrete) keeps the radiation from escaping Different types of reactors [Pressurized Water Reactors] fission of U 235 [Fast Breeder Reactors] Plutonium 239 is used but creates more plutonium as a waste product very dangerous [Fusion reactors] stars are giant fusion reactors inside the sun 1/1H + 2/1D 3/2 He + y Nucleuses are held together by the strong nuclear force Nucleuses are pushed apart by the Colomb force Divided by 1.6 x 10^-19 J eV JeV Multiplied by 1.6 x 10-9 Critical Mass The smallest amount of fissionable material that will, when formed into a ball sustain an uncontrolled chain reaction E=mc2 E=energy m= mass c=3.0 x 10^8ms speed of light WASTES High level- remnants from fuel rods stored in shielded cooled containers Medium level – fuel containers pipes gauges –shielded containers Low level –protective clothing ,water from showers old plant equipment stored for a short time or just released Enrichment of uranium-235 The gas centrifuge process has been widely used in Europe for about 30 years to enrich uranium for the commercial nuclear power market. The process uses a large number of rotating cylinders interconnected to form cascades. The UF6 gas is placed in the cylinder and rotated at a high speed. The rotation creates a strong centrifugal force that draws more of the heavier gas molecules (containing the U238) toward the wall of the cylinder, while the lighter gas molecules (containing the U235) tend to collect closer to the center. The stream that is slightly enriched in U235 is withdrawn and fed into the next higher stage, while the slightly depleted stream is recycled back into the next lower stage. Significantly more U235 enrichment can be obtained from a single gas centrifuge machine than from a single gaseous diffusion stage. GENERAL

E23 = 10^23