## 10/10/2011

### Answers for E.C.E - 2

Answers of questions of   E.C.E 2

1. BAR, which is further equal to 100 kilopascles.
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2. Due to the long term exposure to stress, metal deforms permanently, this phenomenon is          called creeping.
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3. Generally,  flux = flow rate / membrane area.
It is measured by using Ballistic Galvanometer.
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4. An ideal volt meter has infinite internal resistance. It acts as a open circuit.
An ideal am meter has zero internal resistance. It acts as a short circuit.
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5. Implantation defects(defects in substrate) causes the leakage current in transistor. It flows through the pn junction when it is inversely polarized.
Another reason is TiSi gain, which occurs during annealing process.
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6. Generally, the slope of load line depends upon Resistor value.
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7. Direct conversion ACD or  Flash ACD
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8. 8
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9. Logic circuitry, in which more positive voltage or current state represents a state '0', and less positive represents state '1' .
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10. NAND and NOR. They are called universal gates as all other gates can be implemented using them.
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11. For a ideal current source

• internal resistance is infinite
• current in the circuit is independent of voltage across it.
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12. Circular polarized radiation can be obtained by the

• Dipole elements
• Patch elements
• Helical elements
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13. Directivity = maximum directive gain
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14. Broadcasting array or phased array is the arrangement(array) of antennas such that the relative phase of signal changes to get the desired results in one direction.

Uses are AM Broadcasting for day and night

Example is phased array.
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15. According to the Lenz's law,  induced emf causes a flow of current whose magnetic field opposes the change in magnetic flux.
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16. Faraday law of induction
The induced electromotiuve force(emf) is equal to the time rate of change in magnetic flux
through the circuit
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Faraday law of Electrolysis
1st law - The mass of the substance submitted on the electrode during electrolysis is
directly proportional to the amount of electricity or electric charges induced into
electrodes.

2nd law -  For a given quantity of electricity (electric charge), the mass of an material
altered  at an electrode is directly proportional to the element's equivalent weight.
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17.   amps / square meter
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18. By taking the vector sum of the different electric fields at that point.

To add them we use formula E = kq/r
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19. by turning the switch between load and supply at a very fast rate.
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20. Disadvantages of FM over AM are
• More attenution as it is directly proportional to frequency.
• FM waves penetrates ionosphere and do not refracted back.
• Around 20 times more bandwidth
• More complicated receiver and transmitter.
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21. de emphasis circuit is used after demodulator, in which signal is reduced to get the original signal.
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22.Quantization noise in PCM can be reduced by increasing the sampling rate.
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23. They are having very high frequencies, in the range of 30 to 300 GHhz.
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24.  This is the technique to increase the amplitude of the higher frequencies of the modulating signal to enhance the signal to noise ratio.It is done before the transmission.
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25. PCM, as it is a digital modulation system and digital modulation signals are much immune to noise.

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