Physics Unit Test Study Guide PDF

10.1 Light and the Electromagnetic Spectrum Light as a Wave: Light is a form of electromagnetic radiation that behaves as a wave, traveling in straight lines. Electromagnetic Spectrum (EMS): The EMS consists of all electromagnetic waves arranged by wavelength and frequency...

10.1 Light and the Electromagnetic Spectrum Light as a Wave: Light is a form of electromagnetic radiation that behaves as a wave, traveling in straight lines. Electromagnetic Spectrum (EMS): The EMS consists of all electromagnetic waves arranged by wavelength and frequency. Light is part of this spectrum. ○ Visible Light: The portion of the EMS that is visible to the human eye, consisting of different colors. ○ ROYGBIV: The colors of visible light in order: Red, Orange, Yellow, Green, Blue, Indigo, Violet. Additive Colour Theory: Involves combining different colors of light (e.g., red, green, and blue) to produce other colors. Subtractive Colour Theory: Involves mixing pigments (e.g., cyan, magenta, yellow) where each pigment subtracts certain wavelengths from white light. The Universal Wave Equation: ○ v=fλ (v = f \lambdav=fλ) this is probably not right ○ Where: v = wave speed (measured in m/s) f = frequency (measerued un Hz) lambda(λ) = wavelength T=1/fT (= 1/fT=1/f) t represents the period of the wave, which is the time it takes for one complete cycle of the wave to pass a given point. It is usually measured in seconds. f represents the frequency of the wave, which is the number of complete cycles that occur per second. It is typically measured in hertz (Hz), where 1 Hz = 1 cycle per second. 10.2 Producing Visible Light Incandescence: Light produced by heating an object (e.g., light bulb). Luminescence: Light emitted without heat (e.g., glow-in-the-dark objects). Luminous vs. Non-Luminous: ○ Luminous: Objects that emit their own light (e.g., the Sun, light bulbs). ○ Non-Luminous: Objects that reflect light (e.g., the Moon, a table). Types of Luminescence: ○ Phosphorescence: Absorbs light and re-emits it over time (glow-in-the-dark). ○ Fluorescence: Absorbs light and re-emits it almost instantly. ○ Chemiluminescence: Light produced by chemical reactions (e.g., glow sticks). ○ Bioluminescence: Light produced by living organisms (e.g., fireflies, some jellyfish). ○ Triboluminescence: Light produced by friction or pressure (e.g., crushing sugar crystals).  ○ LED: Light-emitting diode, a semiconductor light source. ○ Electric Discharge: Light produced by an electrical current passing through a gas. ○ OLED: Organic light-emitting diode, used in modern displays. ○ Plasma Displays: Use ionized gas to create light. ○ LCD: Liquid Crystal Display, uses liquid crystals to modulate light from a backlight. 10.3 The Ray Model of Light Light Rays: Straight lines used to represent the path of light in ray diagrams. Geometric Optics: Study of light behavior using rays and images. Types of Materials: ○ Opaque: Does not transmit light. ○ Translucent: Allows some light to pass through. ○ Transparent: Allows most light to pass through. Flat Mirrors: ○ Terms: Plane Mirror: A flat mirror. Incident Ray: The ray that strikes the mirror. Reflected Ray: The ray that bounces off the mirror. Normal: A line perpendicular to the surface of the mirror. Angle of Incidence: The angle between the incident ray and the normal. Angle of Reflection: The angle between the reflected ray and the normal. Reflection Types: Specular Reflection: Reflection from a smooth surface. Diffuse Reflection: Reflection from a rough surface. Laws of Reflection: The angle of incidence equals the angle of reflection. The incident ray, reflected ray, and normal all lie in the same plane. Images in Plane Mirrors: ○ Use rays to locate images. ○ SALT: Size (larger, smaller, same) Attitude (upright, inverted) Location (in front, behind) Type (real or virtual) 11.1 Mirrors: Reflection of Light Curved Mirrors: ○ Concave Mirror: Curves inward, can converge light. ○ Convex Mirror: Curves outward, causes light to diverge.  ○ Key Terms: Principal Axis: The line through the center of the mirror. Focal Point (F): The point where parallel rays converge. Center of Curvature (C): The center of the sphere from which the mirror is a segment. ○ Ray Diagrams: Concave: Light rays converge. Convex: Light rays diverge. Mirror and Magnification Equations Magnification Equation: ○ m=hiho=−didom = \frac{h_i}{h_o} = - \frac{d_i}{d_o}m=ho​hi​​=−do​di​​ ○ Where: mmm = magnification hih_ihi​, hoh_oho​= image and object heights did_idi​, dod_odo​= image and object distances Sign Conventions: ○ For concave mirrors: fff is positive, did_idi​is negative for virtual images. ○ For convex mirrors: fff is negative, did_idi​is negative for virtual images. 11.2 Refraction of Light Refraction: The bending of light as it passes from one medium to another. ○ From fast to slow medium: Light bends toward the normal. ○ From slow to fast medium: Light bends away from the normal. Index of Refraction: ○ n=cvn = \frac{c}{v}n=vc​ ○ Where nnn is the index of refraction, ccc is the speed of light in a vacuum, and vvv is the speed of light in the medium. ○ Snell’s Law: n1sin⁡θ1=n2sin⁡θ2n_1 \sin \theta_1 = n_2 \sin \theta_2n1​sinθ1​=n2​sinθ2​ Describes the relationship between angles and the refractive indices of two media. Critical Angle & Total Internal Reflection: ○ Critical Angle: The angle of incidence at which light refracts along the boundary (no refracted ray). ○ Total Internal Reflection: Occurs when light hits the boundary at an angle greater than the critical angle. ○ Applications: Fibre optics, diamonds. 11.3 Lenses and Image Formation  Types of Lenses: ○ Converging (Convex) Lens: Focuses light to a point. ○ Diverging (Concave) Lens: Spreads light out. Ray Diagrams: ○ Converging lenses: Parallel rays converge at the focal point. ○ Diverging lenses: Parallel rays appear to diverge from a point. Thin Lens Equation: ○ 1f=1do+1di\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}f1​=do​1​+di​1​ Magnification: ○ m=−didom = - \frac{d_i}{d_o}m=−do​di​​ 12.1 Human Eye and Vision Parts of the Eye: ○ Cornea: Focuses light. ○ Lens: Further focuses light to the retina. ○ Retina: Contains photoreceptors (rods and cones). ○ Optic Nerve: Transmits signals to the brain. Vision Problems: ○ Hyperopia (Farsightedness): Difficulty seeing close objects. ○ Myopia (Nearsightedness): Difficulty seeing distant objects. ○ Presbyopia: Age-related difficulty focusing on close objects. ○ Astigmatism: Blurred vision due to an irregularly shaped cornea. Corrective Lenses: ○ Concave Lenses: Correct myopia. ○ Convex Lenses: Correct hyperopia. 12.2 Lens Applications Projector Lens: Uses converging lenses to project an image. Magnifying Glass: A simple converging lens used to magnify small objects. Cameras and Eyeglasses: Use lenses to focus light onto the retina or film.