Light Microscope Parts and Functions

Ocular Lenses: Magnification of 10X; equipped with a pointer for identifying specimen features.
Arm: Supports the microscope head; connects to the base and serves as a carrying handle.
Light Intensity Knob: Controls light intensity and power to the bulb; serves as an on/off switch.
Fine Focus Adjustment Knob: Allows for precise focusing, particularly with high magnification lenses; aids in assessing specimen depth.
Coarse Focus Adjustment Knob: Provides rapid focusing for scanning and low power lenses; used only to get the specimen roughly in focus.
Mechanical Stage Adjustment Knobs: Two knobs that enable slide motion; one side-to-side, the other forward and backward, allowing for precise positioning of the slide.
Base: Provides stability and support for the entire microscope.
Lamp: Supplies steady illumination for observing specimens.
Condenser Lens: Directs light from the lamp through the specimen, enhancing clarity.
Iris Diaphragm: Adjusts light entering the specimen for better visibility; located on the condenser.
Stage: Platform that holds slides; has an aperture for light to illuminate specimens.
Stage Clips: Securely fasten slides onto the stage.
Objective Lenses: Produce real images from specimens; available at magnifications of 4X, 10X, 40X, and 100X.
Revolving Nosepiece: Rotatable turret holding objective lenses; facilitates easy switching between lenses.

Resolution: Defines image clarity; improves with better optics.
Limit of Resolution: Minimum distance at which two points are distinguishable.
Numerical Aperture: Quantifies a lens's ability to gather light from the specimen for image formation.
Bright-field Microscopy: Displays a shadowy specimen against a bright background; often requires stains for contrast.
Dark-field Microscopy: Utilizes reflected light; results in a brightly lit specimen against a dark background.
Phase Contrast Microscopy: Enhances contrast based on refractive index differences; produces shades of brightness.
Fluorescence Microscopy: Employs fluorescent dyes; highlights structures under UV lighting.
Parfocal Lenses: Maintain specimen focus when switching objectives.

Depth of Field: Refers to the thickness of specimen in focus; decreases with increased magnification.
Working Distance: Distance from the lens to the specimen; diminishes as magnification rises.
Total Magnification: Calculated by multiplying ocular magnification (10X) with the objective magnification.
Types of Objective Lenses:
- Scanning Lens: 4X magnification, total 40X
- Low Power Lens: 10X magnification, total 100X
- High Power Lens: 40X magnification, total 400X
- Oil Immersion Lens: 100X magnification, total 1000X
Light Microscopy with Stains: Crucial for identifying microbes in clinical samples.
Immersion Oil Benefits: Reduces light loss, increases numerical aperture, improves resolution.
Lens Paper Use: Essential for cleaning lenses smoothly to avoid damage.

Resolution vs. Limit of Resolution: As the limit of resolution decreases, resolution improves.
Image Formation Process: Initiates with light from an internal or external source.