Engineering Studies: Household Appliances Practice Flashcards

Comprehensive flashcards covering parts 1 through 5 of the Household Appliances module, including historical development, materials science, engineering mechanics, and electrical principles.

According to the transcript, what was the first household appliance used for refrigeration?

The icebox, which used wood for the cabinet, sawdust for insulation, and tin or zinc for lining.

What is the key difference between thermopolymers and thermosetting polymers?

Thermopolymers can be melted and re-formed once set, while thermosetting polymers cannot be remelted or reshaped.

Define a 'scalar quantity' as used in engineering mechanics.

A quantity that requires only magnitude (size) for its complete understanding, such as time, distance, or mass.

Define a 'vector quantity' as used in engineering mechanics.

A quantity that requires direction as well as magnitude for its complete understanding, such as force, velocity, or acceleration.

What are the three types of repeating atomic patterns found in crystalline metals?

Hexagonal close packed (HCP), face-centred cubic (FCC), and body-centred cubic (BCC).

State Newton's Second Law of motion as a formula.

$F = m \times a$ where $F$ is force, $m$ is mass, and $a$ is acceleration.

What is the standard value for Earth's gravity ($g$) used in the module's calculations?

$9.8\,m/s^2$, though it is often rounded to $10\,m/s^2$ for simplicity.

What is 'magnetic induction' as described in the glossary?

A process enabling the spin axes of electrons to be aligned, thus creating a magnet.

What alloy of nickel and chromium, patented by Albert Marsh in 1905, is commonly used for toaster elements?

Nichrome.

In electrical engineering, what does 'Ohm's Law' state?

$V = I \times R$, where $V$ is potential difference (Volts), $I$ is current (Amperes), and $R$ is resistance (Ohms).

What is the function of a 'commutator' in an electric motor?

A device for reversing the direction of an electric current in a motor to produce continuous motion.

What is the difference between a 'resultant force' and an 'equilibrant force'?

A resultant represents the net effect of all forces in a system; an equilibrant is an equal force acting in the opposite direction to maintain equilibrium.

What are the three essential parts of an electric appliance as listed in the safety section?

1. An internal wire carrying current at a lethal voltage; 2. Insulation to prevent the frame from becoming live; 3. A frame, casing, or cover.

What does 'RCD' stand for and what is its primary safety function?

Residual Current Device; it disconnects both active and neutral leads if it detects a mismatch between currents, indicating a potential leak or shock hazard.

In engineering communication, what angle is typically used for the left and right sides in an isometric projection?

$30^{\circ}$.

Define 'ductile' as it relates to material properties.

The ability of a material to be stretched without failure.

What is the 'Principle of Transmissibility' in mechanics?

The principle stating that a force can be applied anywhere along its line of action and have the same effect.

What is 'double insulation' in the context of electrical safety?

A method where the user is protected by multiple layers of insulation (usually a polymer casing), removing the need for an external earth connection.

How is 'Power' ($P$) mathematically related to voltage ($V$) and current ($I$)?

$P = V \times I$, measured in Watts ($W$).

What is the purpose of an 'isolating transformer'?

A $240\,V$ to $240\,V$ transformer that helps protect a person in contact with live metal and earth by isolating the secondary circuit from the mains supply.