回答下面问题Part 1: Multiple Choice Questions (2 points each, total 20 points) Choose the best answer for each question. 1.Which of the following is NOT a passive component? a) resistor b) capacitor c) inductor d) transistor 2.What is the primary purpose of modulation in communication systems? a) to reduce noise b) to increase the frequency of the signal c) to improve the quality of the signal d) to transmit the signal over long distances 3.What is the purpose of a voltage regulator? a) to amplify the voltage of the input signal b) to regulate the output voltage to a constant level c) to provide DC power to the load d) to convert AC power to DC power 4.Which theorem is used to simplify complex circuits for analysis? a) Kirchhoff's law b) The venin's theorem c) Faraday's law d) Ohm's law 5.What is the function of a decoder circuit? a) to convert digital signals into analogue signals b) to convert analogue signals into digital signals c) to select one of several output signals based on the input code d) to amplify signals to a higher power level 6.Which is an advantage of using optical fibers over copper wires in communication systems? a) higher cost b) higher bandwidth c) higher resistance to interference d) easier installation and maintenance 7.What does a low-pass filter do? a) allows low-frequency signals to pass through b) allows high-frequency signals to pass through c) blocks all signals above a certain frequency d) blocks all signals below a certain frequency 8.Which type of transistor has higher input impedance: common-emitter or common-base? a) common-emitter b) common-base c) they have the same input impedance d) it depends on the specific circuit configuration 9.What is the function of a mixer in radio communication systems? a) to amplify the received signal b) to combine two or more signals of different frequencies c) to filter out unwanted signals d) to transmit the signal over long distances 10.Which of the following is NOT a type of noise in electronic circuits? a) shot noise b) thermal noise c) cosmic noise d) flicker noise

1. d) transistor
2. d) to transmit the signal over long distances
3. b) to regulate the output voltage to a constant level
4. b) The venin's theorem
5. c) to select one of several output signals based on the input code
6. b) higher bandwidth
7. a) allows low-frequency signals to pass through
8. b) common-base
9. b) to combine two or more signals of different frequencies
10. c) cosmic noise