The frequency range which is called High Frequency band is?
Answer: D
The High Frequency band runs from 3 to 30 MHz.
HF waves are reflected by the ionosphere, so they can travel thousands of kilometres by skywave, which is why short-wave broadcasting, amateur radio and long-range aviation use the band.
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Compact discs, (according to the original CD specifications) hold ------------ many minutes of music?
Answer: A
A compact disc holds 74 minutes of music under the original specification.
The story is that Sony's Norio Ohga insisted the disc hold Beethoven's Ninth Symphony complete, which fixed the diameter at 120 mm. Later discs stretched the format to 80 minutes.
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What does AC and DC stand for in the electrical field?
Answer: A
AC is alternating current and DC is direct current.
In alternating current the direction reverses periodically - 50 times a second in India - which is what allows transformers to change the voltage for transmission. Direct current flows one way only, as from a battery.
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A given signal's second harmonic is twice the given signal's __________ frequency...?
Answer: C
The second harmonic is twice the fundamental frequency.
Any periodic wave can be resolved into a fundamental and harmonics at integer multiples of it. The relative strength of those harmonics is what makes a violin and a flute sound different at the same pitch.
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Voltage is sometimes referred to as EMF, which means Electromotive...?
Answer: D
EMF stands for electromotive force.
Despite the name it is not a force but an energy per unit charge, measured in volts. It is the work a source such as a cell or generator does in driving a unit charge round the circuit.
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"FET" is a type of transistor or ________ Effect Transistor...?
Answer: A
FET stands for field effect transistor.
The current between source and drain is controlled by the electric field of the voltage on the gate, which draws almost no current. That high input impedance is why FETs, and MOSFETs in particular, are used in almost all integrated circuits.
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What is the average power (in watts) used by a 20 to 25 inch home color television...?
Answer: A
A 20 to 25 inch colour television draws about 70 to 100 watts.
Most of it goes to the electron gun and the deflection circuits. A modern LED set of the same size uses a fraction of that.
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