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Sample Practice Test Questions
What's the last gear in a gear train called?
driven gear
A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.
Capacitors store:
electricity
Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.
The formula for the area of a circle is which of the following?
a = π r2
The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)2 : a = π r2.
Which of the following is not a terminal on a transistor?
input
A transistor works by allowing a small amount of current applied at the base to control general current flow from collector to emitter through the transistor.
Which of the following is not an advantage of using a tape measure over using a ruler?
measure with more accuracy
Rulers are used to both measure distance and to draw straight lines. Tape measures are flexible rulers useful for measuring longer distances and in tighter spaces. Rulers and tape measures provide similarly accurate measurements.
The stoichiometric ratio is approximately:
14.7:1
The stoichiometric ratio defines the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air. For gasoline fuel, the stoichiometric ratio is about 14.7:1 or for every one gram of fuel, 14.7 grams of air are required. Too much air results in a lean air-fuel mixture that burns more slowly and hotter while too much fuel results in a rich mixture that burns quicker and cooler.
This tool is a(n) __________.
outside micrometer
Micrometers provide accuracy to the thousandths of an inch and come in outside and inside varieties. An outside micrometer is used to measure outside thickness, such as the diameter of a bolt, while an inside micrometer is used to measure the inside dimension of an object, such as the diameter of the hole of a nut or the width of a channel.
In electrical wiring, which of the following are proportional?
the diameter of the wire and the amount of the current
Current flow through a wire increases the temperature of the wire. If too small a wire is used, the wire will heat up causing a loss in conductivity and possibly a fire. The thicker in diameter a wire is, the more current it can carry without overheating.
What kind of diode allows current to flow in the opposite direction once a certain voltage threshold is reached?
zener diode
A diode allows current to pass easily in one direction and blocks current in the other direction. A zener diode is a diode which allows current to flow in one direction as normal and will also allow current flow in the reverse direction when the voltage is above a certain value. This value is called the breakdown voltage.