Engineering General Flashcards

What is the name for the stress to strain ratio that is lower than the proportional limit?

Answer: Young’s modulus

Young's modulus, also known as the modulus of elasticity, is a material property that quantifies its stiffness. It is defined as the ratio of stress (force per unit area) to strain (proportional deformation) within the elastic region, specifically below the material's proportional limit. This value indicates how much a material will deform elastically under a given load.

What angle, for the following frame depicted most approximately, would guarantee that the frame is in equilibrium?

Answer: 33.7°

To ensure a frame is in equilibrium, the sum of all forces acting on it in both horizontal and vertical directions must be zero, and the sum of all moments about any point must also be zero. Without the specific frame diagram and the forces applied, a detailed calculation cannot be performed. However, 33.7° is a common angle that arises in structural mechanics problems when specific force and geometric configurations are required for static equilibrium.

The same thing as 18,000 watts is

Answer: 18 µW

The prefix 'kilo' (k) denotes 10^3, so 18,000 watts is equivalent to 18 kilowatts (18 kW). The prefix 'micro' (µ) denotes 10^-6. Therefore, 18 µW (microwatts) is 18 x 10^-6 watts, which is a significantly smaller value than 18,000 watts. Based on standard metric prefixes, 18,000 watts is correctly expressed as 18 kW, not 18 µW.

The term for electrons in the outer orbit is

Answer: valences

Valence electrons are the electrons located in the outermost electron shell of an atom. These electrons are critically important because they determine an atom's chemical properties and its ability to form chemical bonds with other atoms. The number of valence electrons dictates an element's reactivity and how it will interact in chemical reactions.

A two-terminal variable resistor is what a potentiometer is.

Answer: False

A potentiometer is fundamentally a three-terminal variable resistor. It consists of a resistive track with two fixed end terminals and a third terminal connected to a movable sliding contact (wiper). While it can be configured as a two-terminal variable resistor (rheostat) by using only one end terminal and the wiper, its inherent design and full functionality involve all three terminals.

13.63 mA is detected when a 12 V battery is connected in series with four resistors of equal value. Each resistor's value is

Answer: 220

In a series circuit, the total resistance is the sum of all individual resistances. According to Ohm's Law (V = I * R), the total resistance (R_total) can be calculated as V_total / I_total. Given a 12 V battery and a total current of 13.63 mA (0.01363 A), R_total = 12 V / 0.01363 A ≈ 880.4 Ω. Since there are four equal resistors in series, each resistor's value is R_total / 4 = 880.4 Ω / 4 ≈ 220.1 Ω, which rounds to 220 Ω.

A 1/8 W resistor, a 1/4 W resistor, and a 1/2 W resistor make up a specific series circuit. 1200 people are resisting in all. If each resistor in the circuit is working at its maximum power dissipation, total current flow is

Answer: 27 mA

In a series circuit, the current is uniform through all components. To find the total current when each resistor operates at its maximum power dissipation, we use the formula P = I²R. The total resistance is 1200 Ω, and the sum of the maximum power dissipations is 1/8 W + 1/4 W + 1/2 W = 7/8 W. Since P_total = I² * R_total, we have (7/8) W = I² * 1200 Ω. Solving for I, I = sqrt((7/8) / 1200) ≈ 0.0270 A, which is approximately 27 mA.

A parallel circuit acts as a current divider.

Answer: True

A parallel circuit functions as a current divider because the total current entering a junction splits among the various parallel branches. The current flowing through each branch is inversely proportional to its resistance, meaning that more current will take the path of least resistance. This characteristic effectively divides the total current among the different paths.

Electricity delivered to the secondary load is 25 W if 25 W of power are applied to the primary of an ideal transformer with a turns ratio of 10.

Answer: 25 W

An ideal transformer is characterized by having no energy losses, meaning it operates with 100% efficiency. Consequently, all the power supplied to the primary coil is perfectly transferred to the secondary coil. Therefore, if 25 W of power are applied to the primary, exactly 25 W of power will be delivered to the secondary load, irrespective of the transformer's turns ratio.

What is the coupling coefficient for a transformer in which the secondary does not receive 4% of the total flux generated in the primary?

Answer: 0.96

The coupling coefficient (k) for a transformer represents the fraction of the total magnetic flux generated in the primary coil that successfully links with the secondary coil. If 4% of the total flux does *not* link with the secondary, it means that 96% of the flux *does* link. Therefore, the coupling coefficient is 0.96, indicating a high degree of magnetic linkage between the coils.

When is it acceptable for a certified engineer to sign and seal blueprints or legal papers that they did not create?

Answer: If the registered engineer is an authority on the subject and someone who worked under their supervision developed the designs or documentation.

Professional engineering ethics and regulations generally permit a registered engineer to sign and seal documents they did not personally create only under specific conditions. The most critical condition is that the engineer must have direct supervisory control over the work's development and be an authority on the subject, allowing them to thoroughly review, approve, and take full professional responsibility for the designs or documentation. This ensures accountability and adherence to professional standards.