How would the illustration look if it were showing a step-down transformer?

A model-train transformer plugs into 120 V ac, and draws 0.75 A while supplying $15 ~\mathrm{A}$ to the train.

(a) What voltage is present across the tracks? (b) Is the transformer step-up or step-down?

Consider a very long rectangular fin attached to a flat surface such that the temperature at the end of the fin is essentially that of the surrounding air, i.e., $20^{\circ} \mathrm{C}.$ Its width is 5.0 cm; thickness is 1.0 mm; thermal conductivity is $200 \mathrm{W} / \mathrm{m} \cdot \mathrm{K};$ and base temperature is $40^{\circ} \mathrm{C}.$ The heat transfer coefficient is $20 \mathrm{W} / \mathrm{m}^{2} \cdot \mathrm{K}.$ Estimate the fin temperature at a distance of 5.0 cm from the base and the rate of heat loss from the entire fin.

How would the illustration look if it were showing a step-down transformer?

A $220 / 20-\mathrm{V}$ transformer has 50 turns on its low-voltage side. Calculate: a. The number of turns on its high side. b. The turns ratio $\alpha$ when it is used as a step-down transformer. c. The turns ratio $\alpha$ when it is used as a step-up transformer.

A step-up transformer is used to connect a lightbulb to a wall outlet. What happens to the brightness of the lightbulb if the transformer is replaced with a stepdown transformer?

A step-up transformer has more windings on the ______ coil.

Hot water flows through a PVC $(k=0.092 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K})$ pipe whose inner diameter is $2 \mathrm{~cm}$ and whose outer diameter is $2.5 \mathrm{~cm}$. The temperature of the interior surface of this pipe is $35^{\circ} \mathrm{C}$, and the temperature of the exterior surface is $20^{\circ} \mathrm{C}$. The rate of heat transfer per unit of pipe length is (a) $22.8 \mathrm{~W} / \mathrm{m}$ (b) $38.9 \mathrm{~W} / \mathrm{m}$ $(c)$ $48.7 \mathrm{~W} / \mathrm{m}$ (d) $63.6 \mathrm{~W} / \mathrm{m}$ (e) $72.6 \mathrm{~W} / \mathrm{m}$

A high-intensity desk lamp is rated at $35 \mathrm{~W}$ but requires only $12 \mathrm{~V}$. It contains a transformer that converts $120~\mathrm{V}$ household voltage. Is the transformer step-up or step-down?

A model-train transformer plugs into 120-V ac and draws 0.35 A while supplying 7.5 A to the train. Is the transformer step-up or step-down?

Can an efficient transformer step up energy? Defend your answer.

In order to match a source with internal impedance of 500 $\Omega$ to a 15-$\Omega$ load, what is needed is: (a) step-up linear transformer (b) step-down linear transformer (c) step-up ideal transformer (d) step-down ideal transformer (e) autotransformer

A step-down transformer is used for recharging the batteries of portable devices such as tape players. The turns ratio inside the transformer is $13: 1$ and it is used with $120-\mathrm{V}$ (rms) household service. If a particular ideal transformer draws $0.350 \mathrm{~A}$ from the house outlet, what are (a) the voltage and (b) the current supplied to a tape player from the transformer? (c) How much power is delivered?

A model-train transformer plugs into $120-\mathrm{V}$ ac and draws $0.35 \mathrm{~A}$ while supplying $7.5 \mathrm{~A}$ to the train. (b) Is the transformer step-up or step-down?