Physics 124 Lab Manual Practice Flashcards

This set covers administrative lab rules, measurement theory, electromagnetism, optics, and human eye anatomy based on the Physics 124 Lab Manual (Spring 2026).

Accuracy

A measurement of how close a value is to the actual or true measurement.

Precision

The reproducibility of a measurement, which also takes into account the scale of the measuring instrument.

Errors

Variations present in measurements due to the lack of precision in the instrument being used.

Mistakes

Inaccuracies that occur because the experimenter is not paying enough attention to laboratory tasks.

Random Error

An error that occurs inconsistently, such as reading a length incorrectly.

Consistent Error

An error that persists through every measurement, such as having a ruler offset by a fixed amount (e.g., $1\,cm$).

Coulomb's Law

The law stating that the electrostatic force $F$ between two charges is proportional to the product of the charges ($q_1q_2$) and inversely proportional to the square of the distance ($r$) between them: $F = \frac{1}{4\pi\epsilon_o} \frac{q_1q_2}{r^2}$.

Permittivity constant ($\epsilon_o$)

A constant value equal to $8.854 \times 10^{-12}\,coulomb^2/(newton-meter^2)$ used in electrostatic force calculations.

Van de Graaff generator

An electrostatic machine that uses a moving belt to accumulate high voltages on a hollow metal globe.

Volt

The amount of work per unit charge required to move a charge between two positions in an electric field; equivalent to $1\,joule$ of work per $1\,coulomb$ of charge.

Electric field

A property of the space surrounding an electric charge that exerts force on other charged objects.

Equipotential line

A line drawn in an electric field that connects all points at the same potential and is always at right angles to the electric lines of force.

Ohm's Law

The principle that the potential difference ($V$) across a circuit is directly proportional to the current ($I$) flowing through it, expressed as $V = I \times R$.

Current

A measure of the amount of charge that passes a given point in a circuit per unit time, measured in amperes.

Resistance

A measure of the difficulty that charges encounter as they move through a circuit element, measured in ohms ($\Omega$).

Resistivity ($\rho$)

A material-dependent property used to calculate resistance using the formula $R = \rho \frac{L}{A}$, where $L$ is length and $A$ is cross-sectional area.

Kirchhoff’s First Law

The rule stating that the total current entering a junction must be equal to the current leaving the junction.

Kirchhoff’s Second Law

The rule stating that the sum of all voltage drops around a closed circuit is zero.

Magnetic Force ($F_B$)

The force on a current-carrying wire in a magnetic field, calculated as $F_B = I L \times B$, where $I$ is current, $L$ is wire length, and $B$ is magnetic field strength.

Faraday’s Law of Induction

The law stating that the magnitude of the induced emf ($\xi$) in a circuit is proportional to the rate of change of magnetic flux ($\Phi_B$).

Lenz’s Law

The physical principle stating that the direction of an induced current is such as to oppose the change in the applied magnetic field.

Refraction

The bending of a wave when it enters a medium where its speed is different, such as light moving from air into glass.

Snell's Law

The quantitative description of the amount of bending that occurs when light passes between two media with different indices of refraction.

Exponential Decay

A decline in which the rate of decay is always proportional to the amount of material remaining, used to model light intensity as it passes through absorbers.

Plane polarized light

Light in which the electric field vibrates in only one specific direction or plane.

Polarizer

A device that only allows light vibrating in a particular plane (the axis of polarization) to pass through it.

Convex lenses

Lenses that are thicker at the middle than at the edges and bring parallel rays of light together at a focal point.

Concave lenses

Lenses that are thinner at the middle than at the edges and cause parallel rays to spread out as if diverging from a point.

Vitreous humor

A transparent jelly-like substance that fills the dark chamber of the human eye.

Fovea centralis

A region on the retina about $0.3\,mm$ in diameter that represents the area of greatest visual sensitivity.

Blind spot

An insensitive region on the retina where the optic nerve leaves the eye, containing no rods or cones.

Ciliary muscle

An annular muscle that controls the curvature of the crystalline lens to allow the eye to focus on objects at different distances.

Distance of distinct vision

The minimum distance to which the eye can adapt for clear focus, averaging about $25\,cm$.

Hyperopia

Far-sightedness; a condition caused by a shorter-than-normal eyeball where images of near objects form behind the retina.

Myopia

Near-sightedness; a condition caused by a longer-than-normal eyeball where images of far objects form in front of the retina.

Astigmatism

An eye defect where the lens surfaces are not rotationally symmetrical, causing lines of certain orientations to appear blurred.