Physics: Optics and Electrical Charges Flashcards
Coulomb’s Law
Coulumbic force
- Fq= k•q1•q2/r2
q: charge
r: distance
k: constant
F: negative (attractive)
F: positive (repulsion)
Electric fields
A charge particle that is moving or static experiences a push or force.
Vectors
Magnitude:
- E= voltage/distance
- E= force/charge
- FE= qE
Direction: positive to negative
Electron potential
Determines the electrical potential energy ( Volts )
Volts at a spot= electrical potential
- formula: V= k•q/1
Real images vs Virtual image
Real image
- actual light passing through
- mirror: image on same side as object
- lens: image opposite side of object
Virtual image
- extrapolated light passing through
- mirror: image opposite side of object
- lens: image same side of object.
Electrical potential energy and voltage
Objects have potential energy due to charge. Electric field pushes or pulls and object based on charge.
- Formula: Volts • charge (q)
Voltage is difference in electrical potential
Thin lens and magnification
Thin lens
- formula: 1/o + 1/i =1/f
- Lens power: P= 1/f
Magnification formula: -i/o
- m= (-) upside down image
- m= 0-1 small
- m= m>1 large
Refraction
Snells law
- n•sin θ= n ₂•sin θ ₂
- smaller sin θ, greater n
n= c/v
- n: index of refraction
- c: speed of light in a vacuum
- v: speed of light of material in question
Law of reflection Reflection
Angle of incidence= angle of reflection
Refraction and total internal reflection
Angle of incidence < critical angle
- light refracts away from normal
Angle of incidence = critical angle
- light refracts at 90 degrees to the normal.
Angle of incidence > critical angle
- total internal reflection
Mirrors
Converging mirror (at focus): no image
Converging mirror (outside focus): real image
Converging mirror (inside focus): virtual image
Diverging mirror anywhere: virtual image
- focal length negative
