Constructivism holds that learners build their own understanding and knowledge through their experiences, and then reflect on those experiences. Key theorists include Piaget and Vygotsky. Behaviorism focuses on observable behaviors and stimulus-response patterns, while Realism is a philosophical stance about the nature of the external world.

Correct Answer: C — Constructivism.

Resistivity ($\rho$) is the reciprocal of conductivity ($\sigma$).

$\sigma = ne\mu_e$

Given: $n = 10^{19} \text{ m}^{-3}$, $\mu_e = 1.6 \text{ m}^2/\text{Vs}$, and $e = 1.6 \times 10^{-19} \text{ C}$.

$\sigma = 10^{19} \times (1.6 \times 10^{-19}) \times 1.6 = 1.6 \times 1.6 = 2.56 \ \Omega^{-1}\text{m}^{-1}$.

$\rho = \frac{1}{\sigma} = \frac{1}{2.56} \approx 0.39 \ \Omega\text{m}$.

The closest value provided is $0.4 \ \Omega\text{m}$.

This statement is attributed to Armstrong, who described the discovery method (also called the Heuristic method) as one in which students investigate and discover knowledge independently, much like scientists. Armstrong was also an early proponent of the Heuristic method in science education.

Correct Answer: C — Armstrong.

Set revenue $\geq$ cost:

$500x \geq 9{,}000 + 400x$

$100x \geq 9{,}000$

$x \geq 90$

The minimum number of refrigerators is $\mathbf{90}$.

For $h \ll R$, orbital radius $\approx R$:

Orbital speed: $v_o = \sqrt{gR}$

Escape speed from surface (approximately same radius): $v_e = \sqrt{2gR}$

Minimum increase: $\Delta v = v_e - v_o = \sqrt{2gR} - \sqrt{gR} = \sqrt{gR}(\sqrt{2}-1)$

IV drip rate calculation:

\\text{Drip Rate (drops/min)} = \\frac{\\text{Volume (mL)} \\times \\text{Drop factor (drops/mL)}}{\\text{Time (minutes)}}

= \\frac{1000 \\text{ mL} \\times 20 \\text{ drops/mL}}{8 \\times 60 \\text{ min}}

= \\frac{20{,}000}{480} = 41.67 \\approx 42 \\text{ drops/min}

Common IV drop factors:

• Macro-drip sets: 10, 15, or 20 drops/mL
• Micro-drip sets: 60 drops/mL (used for pediatrics and precise small-volume infusions)

This is a frequently tested calculation in Charge/Head Nurse examinations. Always verify the drop factor printed on the IV administration set packaging.