What increase in sound level is commonly perceived by most people? A. 6 to 10 dB B. 1 to 3 dB C. 3 to 6 dB D. 10 to 20dB

What increase in sound level is commonly perceived by most people?
A. 6 to 10 dB
B. 1 to 3 dB
C. 3 to 6 dB
D. 10 to 20dB
by

1 Answer

Answer :

A. 6 to 10 dB
by

Related questions

For the safety and comfort of factory workers, the sound-intensity level in a certain factory must remain below 85 dB. What is the maximum sound intensity allowed in this factory? A. 3.2 x 10-4 W/m2 B. 3.2 x 10-6 W/m2 C. 3.2 x 10-10 W/m2 D. 3.2 x 10-3 W/m2

Description : For the safety and comfort of factory workers, the sound-intensity level in a certain factory must remain below 85 dB. What is the maximum sound intensity allowed in this factory? A. 3.2 x 10-4 W/m2 B. 3.2 x 10-6 W/m2 C. 3.2 x 10-10 W/m2 D. 3.2 x 10-3 W/m2

Last Answer : A. 3.2 x 10-4 W/m2

A choir consisting of 36 individuals all of whom can sing with the same intensity. A soloist sings a certain passage and then is joined by the remainder of the choir members for a repeat of the passage. What is the difference in the sound intensity level in the two cases? A. 3 dB B. 6 dB C. 36 dB D. 15.6dB

Description : A choir consisting of 36 individuals all of whom can sing with the same intensity. A soloist sings a certain passage and then is joined by the remainder of the choir members for a repeat of the passage. What is the ... sound intensity level in the two cases? A. 3 dB B. 6 dB C. 36 dB D. 15.6dB

Last Answer : D. 15.6dB

ECE Board Exam March 1996 A car horn outdoors produces a sound intensity level of 90 dB at 10 ft away. At this distance, what is the sound power in watt? A. 12 W B. 0.12 W C. 0.012 W D. 1.2 W

Description : ECE Board Exam March 1996 A car horn outdoors produces a sound intensity level of 90 dB at 10 ft away. At this distance, what is the sound power in watt? A. 12 W B. 0.12 W C. 0.012 W D. 1.2 W

Last Answer : C. 0.012 W

The sound power level of a jet plane flying at a height of 1 km is 160 dB. What is the maximum sound pressure level on the ground directly below the plane assuming that the aircraft radiates sound equally in all directions? A. 59.1 dB B. 69.1 dB C. 79.1 dB D. 89.1 dB

Description : The sound power level of a jet plane flying at a height of 1 km is 160 dB. What is the maximum sound pressure level on the ground directly below the plane assuming that the aircraft radiates sound equally in all directions? A. 59.1 dB B. 69.1 dB C. 79.1 dB D. 89.1 dB

Last Answer : D. 89.1 dB

The sound intensity received from the nearby jet plane is 12.6 µW/m2 and that from another jet plane some distance away is 0.45 µW/m2 . Find the relative loudness of the two. A. 14.0 dB B. 14.5dB C. 12.5 D. 14.5

Description : The sound intensity received from the nearby jet plane is 12.6 µW/m2 and that from another jet plane some distance away is 0.45 µW/m2 . Find the relative loudness of the two. A. 14.0 dB B. 14.5dB C. 12.5 D. 14.5

Last Answer : B. 14.5dB

You are measuring noise at a -6 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -59 dBm. This is _________ dBa0. A. 24 B. 12 C. 23 D. 32

Description : You are measuring noise at a -6 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -59 dBm. This is _________ dBa0. A. 24 B. 12 C. 23 D. 32

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Description : What is the gain of an antenna over a half-wavelength dipole when it has 6 dB gain over an isotropic radiator? A. 6.0 dB B. 8.1 dB C. 3.9 dB D. 10.0 dB

Last Answer : C. 3.9 dB

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Description : Determine the dB gain of a receiving antenna which delivers a microvolt signal to a transmission line over that of an antenna that delivers a 20 microvolt signal under identical circumstances. A. 10 dB B. 6 dB C. 3 dB D. 8 dB

Last Answer : B. 6 dB

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Description : What is the gain of four identically polarized antennas stacked one above the other and fed in phase? A. 3 dB over the gain of one antenna B. 10 dB over the gain of one antenna C. 4 dB over the gain of one antenna D. 6 dB over the gain of one antenna

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Description : At what power level does a 1 KHz tone cause zero interference (144 weighted)? A. 90 dB B. 90 dBm C. -90 dBm D. -90 dBm

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Last Answer : A. 75

You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -57dBm. This is ________dBa0. A. 20 B. 15 C. 25 D. 17

Description : You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -57dBm. This is ________dBa0. A. 20 B. 15 C. 25 D. 17

Last Answer : C. 25

What is the required quality factor for an SSB filter with the following data: center frequency= 1 MHz, the desired attenuation level of the unwanted sideband= 80 dB and the separation between sidebands= 200 Hz? A. 1,250 B. 12,500 C. 125,000 D. 25,000

Description : What is the required quality factor for an SSB filter with the following data: center frequency= 1 MHz, the desired attenuation level of the unwanted sideband= 80 dB and the separation between sidebands= 200 Hz? A. 1,250 B. 12,500 C. 125,000 D. 25,000

Last Answer : C. 125,000

For a loudness level between 110 and 120 dB, the maximum daily exposure limit is ____ minute (s). A. 1 B. 60 C. 20 D. 45

Description : For a loudness level between 110 and 120 dB, the maximum daily exposure limit is ____ minute (s). A. 1 B. 60 C. 20 D. 45

Last Answer : A. 1

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Description : What loudness level in which permanent damage to hearing is possible? A. 120 dB B. 140 dB C. 130 dB D. 150 dB

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At what loudness level do pitch (in mels) and frequency (in Hz) are numerically equal? A. 0 dB B. 20 dB C. 60 dB D. 40 dB

Description : At what loudness level do pitch (in mels) and frequency (in Hz) are numerically equal? A. 0 dB B. 20 dB C. 60 dB D. 40 dB

Last Answer : D. 40 dB

You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What is the reading in dBrnc? A. 20 B. 32 C. 35 D. 25

Description : You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What is the reading in dBrnc? A. 20 B. 32 C. 35 D. 25

Last Answer : C. 35

You are measuring a voice channel at a -4 dB test point level, the meter reads -73 dBm (pure test tone) convert the reading in dBmCO. A. 16 B. 18 C. 22 D. 12

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Last Answer : C. 22

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In measuring noise in a voice channel at a 4 dB test point level, the meter reads -70 dBm (F1A weighted), convert the reading to pWp. A. 53 B. 93 C. 63 D. 83

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Last Answer : B. 93

ECE Board Exam March 1996 At what power level does a 1 kHz tone cause zero interference (144 weighted) ? A. -90 dB B. -90 dBm C. 90 dBm D. 90 dB

Description : ECE Board Exam March 1996 At what power level does a 1 kHz tone cause zero interference (144 weighted) ? A. -90 dB B. -90 dBm C. 90 dBm D. 90 dB

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A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW. What is the gain in dB, obtained by the use if the reflector. (Gain referred to this particular dipole). A. 4.75 B. 2.6 C. 1.81 D. 4.24

Description : A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW ... Gain referred to this particular dipole). A. 4.75 B. 2.6 C. 1.81 D. 4.24

Last Answer : B. 2.6

The total space loss of transmission and reception for two ground stations with uplink frequency 8GHz and a downlink of 6 GHz with angle of elevations of 3˚ and 7˚ A respectively is A. 403 dB B. 100 dB C. 20 dB D. 215 dB

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Last Answer : A. 403 dB

Which noise figure represents the lowest noise in receiver? A. 1.6 dB B. 2.1 dB C. 2.7 dB D. 3.4 dB

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What is the effective radiated power of a repeater with 75 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? A. 37.6 W B. 237 W C. 150 W D. 23.7 W

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Last Answer : A. 37.6 W

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Description : What is the effective radiated power of a repeater with 50 watts transmitter power output \, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna gain? A. 158 W B. 39.7 W C. 251 W D. 69.9 W

Last Answer : B. 39.7 W

How does the gain of a parabolic dish type antenna change when the operating frequency is doubled? A. Gain does not change B. Gain is multiplied by 0.707 C. Gain increases 6 dB D. Gain increases 3 dB

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Last Answer : C. Gain increases 6 dB

If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter? A. 70 watts B. 50 watts C. 25 watts D. 6 watts

Description : If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter? A. 70 watts B. 50 watts C. 25 watts D. 6 watts

Last Answer : D. 6 watts

Determine the gain of a 6 ft. parabolic dish operating at 1800 MHz. A. 30 dB B. 11.2 dB C. 15.5 dB D. 28.17 dB

Description : Determine the gain of a 6 ft. parabolic dish operating at 1800 MHz. A. 30 dB B. 11.2 dB C. 15.5 dB D. 28.17 dB

Last Answer : D. 28.17 dB

What is the power loss of a telephone hybrid? A. 6 dB B. 2 dB C. 3 dB D. 1 dB

Description : What is the power loss of a telephone hybrid? A. 6 dB B. 2 dB C. 3 dB D. 1 dB

Last Answer : C. 3 dB

What is the free space loss, in dB, between two microwave parabolic antennas 38.0 kilometer apart operating at 7.0 GHz? A. 145.6 dB B. 138.5 dB C. 135.5 dB D. 140.89 dB

Description : What is the free space loss, in dB, between two microwave parabolic antennas 38.0 kilometer apart operating at 7.0 GHz? A. 145.6 dB B. 138.5 dB C. 135.5 dB D. 140.89 dB

Last Answer : D. 140.89 dB

A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 kW. What is the gain in dB obtain by the use of the reflector ? ( Gain referred to this particular dipole) A. 4.24 B. 1.81 C. 4.75 D. 2.6

Description : A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 ... ( Gain referred to this particular dipole) A. 4.24 B. 1.81 C. 4.75 D. 2.6

Last Answer : D. 2.6

What is the gain, in dB of a helical antenna with diameter of λ/3, 10 turns at pitch of λ/4, used at 100 MHz? A. 16 B. 41.1 C. 31.4 D. 1.25

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Last Answer : A. 16

What is the front-to-back ratio of an antenna which radiates 500 watts in a northernly direction and 50 watts in a southernly direction? A. 25000 dB B. 10 dB C. 100 dB D. 20 dB

Description : What is the front-to-back ratio of an antenna which radiates 500 watts in a northernly direction and 50 watts in a southernly direction? A. 25000 dB B. 10 dB C. 100 dB D. 20 dB

Last Answer : B. 10 dB

If an antenna has a gain of 3 dB, it increases the output of the transmitter by A. 10,000 times B. 1000 times C. 100 times D. 1 million times

Description : If an antenna has a gain of 3 dB, it increases the output of the transmitter by A. 10,000 times B. 1000 times C. 100 times D. 1 million times

Last Answer : B. 1000 times

The noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB? A. 11.59 dB B. 11.23 dB C. 10.79 dB D. 10.5 dB

Description : The noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB? A. 11.59 dB B. 11.23 dB C. 10.79 dB D. 10.5 dB

Last Answer : C. 10.79 dB

Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N? A. 5.23 dB B. 14.77dB C. 30 dB D. 40 dB

Description : Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N? A. 5.23 dB B. 14.77dB C. 30 dB D. 40 dB

Last Answer : A. 5.23 dB

What signal-to-noise ratio is required for satisfactory television reception? A. 10 dB B. 30 dB C. 40 dB D. 20 dB

Description : What signal-to-noise ratio is required for satisfactory television reception? A. 10 dB B. 30 dB C. 40 dB D. 20 dB

Last Answer : C. 40 dB

What is the effective radiated power of a repeater with 200 watts transmitter power output, 4 dB feline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 317 W B. 2000 W C. 126 W D. 260 W

Description : What is the effective radiated power of a repeater with 200 watts transmitter power output, 4 dB feline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 317 W B. 2000 W C. 126 W D. 260 W

Last Answer : A. 317 W

What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 800 W B. 126 W C. 12.5 W D. 1260 W

Description : What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 800 W B. 126 W C. 12.5 W D. 1260 W

Last Answer : B. 126 W

What is the effective radiated power of a repeater with 75 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna gain? A. 600 W B. 75 W C. 18.75 W D. 150 W

Description : What is the effective radiated power of a repeater with 75 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna gain? A. 600 W B. 75 W C. 18.75 W D. 150 W

Last Answer : D. 150 W

Part of a microwave link can be approximated by free space conditions. The antenna gain are each 40 dB, the frequency is 10 GHz, and the path length is 80 km. Calculate the receive power for a transmitted power of 10 W? A. 0.871 μW B. 871 μW C. 0.871 mW D. 871 nW

Description : Part of a microwave link can be approximated by free space conditions. The antenna gain are each 40 dB, the frequency is 10 GHz, and the path length is 80 km. Calculate the receive power for a transmitted power of 10 W? A. 0.871 μW B. 871 μW C. 0.871 mW D. 871 nW

Last Answer : A. 0.871 μW

A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is supplied to one end of the line, how many watts reach the load, 27 m away? A. 10 W B. 7.2 W C. 9.9 W D. 9.1 W

Description : A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is supplied to one end of the line, how many watts reach the load, 27 m away? A. 10 W B. 7.2 W C. 9.9 W D. 9.1 W

Last Answer : D. 9.1 W

The noise from an airplane engine 100 ft from an observer is found to have an intensity of 45dB. What will be the intensity when the plane flies overhead at an altitude of 1 mi? A. 10.5 dB B. 34.5 dB C. 35 dB D. 20.5 dB

Description : The noise from an airplane engine 100 ft from an observer is found to have an intensity of 45dB. What will be the intensity when the plane flies overhead at an altitude of 1 mi? A. 10.5 dB B. 34.5 dB C. 35 dB D. 20.5 dB

Last Answer : A. 10.5 dB

The signal to noise ratio that is required for a satisfactory television reception. A. 30 dB B. 40 dB C. 10 dB D. 20 dB

Description : The signal to noise ratio that is required for a satisfactory television reception. A. 30 dB B. 40 dB C. 10 dB D. 20 dB

Last Answer : B. 40 dB

The standard test tone A. 0dB B. 10 dBm C. 0 dBm D. 10 dB

Description : The standard test tone A. 0dB B. 10 dBm C. 0 dBm D. 10 dB

Last Answer : C. 0 dBm

If voltage change equal to twice its original value, what is its corresponding change in dB? A. 9 dB B. 6dB C. 10 dB D. 3dB

Description : If voltage change equal to twice its original value, what is its corresponding change in dB? A. 9 dB B. 6dB C. 10 dB D. 3dB

Last Answer : B. 6dB

Cable attenuation is usually expressed in terms of a. Loss per foot b. dB/km c. intensity per mile d. voltage drop per inch

Description : Cable attenuation is usually expressed in terms of a. Loss per foot b. dB/km c. intensity per mile d. voltage drop per inch

Last Answer : b. dB/km