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Sample Practice Test Questions
What is the primary difference between a rectifier and an inverter?
a rectifier converts an AC input to DC while an inverter converts a DC input to AC
A diode allows current to pass easily in one direction and blocks current in the other direction. Diodes are commonly used for rectification which is the conversion of alternating current (AC) into direct current (DC). Because a diode only allows current flow in one direction, it will pass either the upper or lower half of AC waves (half-wave rectification) creating pulsating DC. Multiple diodes can be connected together to utilize both halves of the AC signal in full-wave rectification.
This skeletal system is common in arthropods like insects, spiders, and crustaceans.
exoskeleton
An exoskeleton (external skeleton) is common in arthropods like insects, spiders, and crustaceans.
Convert 0C° to F°.
32
To convert from C° to F° use:
\(F° = {9 \over 5}C° + 32\)
\(F° = {9 \over 5}(0) + 32\)
\(F° = 0 + 32 = 32\)
Which of the following describes the Earth's outer core?
liquid
The Earth's core is divided into the liquid outer core (1,430 miles or 2,300 km radius) and the solid inner core (745 miles or 1,200 km radius).
Which of the following nuts prevent loosening via nylon in their threads?
lock
Wrenches are used with threaded fasteners like bolts and nuts. A bolt has external threads while a nut has internal threads and this thread pattern combination allows them to lock together and act as fasteners. Nuts come in a variety of configurations including wing nuts which provide appendages that allow tightening and loosening by hand, slotted nuts that use a cotter pin to lock the nut in place and prevent it from loosening, and lock nuts that also prevent loosening via nylon in their threads. Threads are identified by pitch which is the number of threads per inch.
Which of these layers is found directly below the Earth's crust?
mantle
The crust is the Earth's outermost layer and is divided into oceanic and continental types. Oceanic crust is 3 miles (5 km) to 6 miles (10 km) thick and is composed primarily of denser rock. Continental crust is 20 to 30 miles (30 to 50 km) thick and composed primarily of less dense rock. The crust makes up approximately one percent of the Earth's total volume.
Find the average of the following numbers: 17, 13, 17, 13.
To find the average of these 4 numbers add them together then divide by 4:
\( \frac{17 + 13 + 17 + 13}{4} \) = \( \frac{60}{4} \) = 15