Exam: TOEFL

Definition: A small electronic component that allows electricity to flow in one direction only, often used to convert alternating current to direct current.

Example: The technician replaced the faulty diode in the circuit to restore proper function.

Definition: A type of hydrocarbon that contains two double bonds between carbon atoms.

Example: Diolefins are important in the production of synthetic rubber.

Definition: A unit used to measure how strongly a lens can bend light, which is calculated by taking the inverse of the distance from the lens to the point where it focuses light, measured in meters.

Example: The optometrist prescribed glasses with a diopter of -2.5 to correct my vision.

Definition: A unit of measurement used to express the optical power of a lens or mirror, equal to the reciprocal of the focal length in meters.

Example: The optometrist measured my vision and prescribed glasses with a strength of +2.5 dioptres.

Definition: A clear, colorless liquid that can catch fire and is used to dissolve substances like fats and resins in products such as paints and cosmetics.

Example: Dioxane is often used in laboratories as a solvent for various chemical reactions.

Definition: A chemical compound made of one metal atom and two oxygen atoms.

Example: Carbon dioxide is a common example of a dioxid.

Definition: A chemical compound that has two oxygen atoms in each molecule.

Example: Carbon dioxide is produced when we breathe out.

Definition: A group of harmful chemical compounds that can cause cancer and birth defects, often found as pollutants from industrial processes and certain herbicides.

Example: Dioxins are dangerous pollutants that can accumulate in the food chain and pose serious health risks.

Definition: To lower or drop down slightly, often temporarily, or to sink out of sight suddenly.

Example: The sun dipped below the horizon, painting the sky with beautiful colors.

Definition: A quick immersion or plunge into a liquid, often for swimming or tasting food.

Example: She took a dip in the cool lake on a hot summer day.

Definition: To put something into a liquid for a short time, usually to cover it or change its color.

Example: She decided to dip the strawberries in chocolate before serving them.

Definition: A type of enzyme that helps break down dipeptides into individual amino acids.

Example: Dipeptidase is essential for protein digestion in the body.