What is considered the threshold of audibility at 3000 Hz?
A. 10-12 W/m2
B. 10-16 W/m2
C. 10-12 W/cm2
D. 10-15 W/cm2

1 Answer

Answer :

A. 10-12 W/m2

Related questions

Description : The agreed standard for measuring loudness is the loudness sensation produced by a 1000 Hz sine wave _____ dB above the listener’s threshold of hearing. A. 80 B. 50 C. 30 D. 40

Last Answer : D. 40

Description : A frequency of 3000 Hz has how many octaves above 1000 Hz? A. 1.6 octaves B. 2.1 octaves C. 1 octave D. 3 octaves

Last Answer : A. 1.6 octaves

Description : A speaker cabinet has an internal volume 84,950 cm3 . It has a port area on the baffle of 3,230 cm2 and baffle thickness of 19 mm. What is the Helmholtz resonance hertz of this speaker enclosure? A. 260 Hz B. 245 Hz C. 265 Hz D. 250 Hz

Last Answer : B. 245 Hz

Description : The laser frequency when the light has the wavelength 800 nm is a. 375 x 10^12 Hz b. 475 x 10^15 Hz c. 375 x 10^9 Hz d. 375 x 10^18 Hz

Last Answer : a. 375 x 10^12 Hz

Description : Industrial noise frequency is between _____. A. 0 to 10 KHz B. 160 MHz to 200 MHz C. 15 to 160 MHz D. 200 to 3000 MHz

Last Answer : C. 15 to 160 MHz

Description : Industrial noise frequency is between _________. A. 200 to 3000 Mhz B. 15 to 160 Mhz C. 0 to 10 Khz D. 20 Ghz

Last Answer : B. 15 to 160 Mhz

Description : The live load to be considered for an inaccessible roof, is (A) Nil (B) 75 kg/m2 (C) 150 kg/cm2 (D) 200 kg/m

Last Answer : Answer: Option B

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

Description : A single phase transformer rated at 3000 kVA, 69 kV 4.16 kV, 60 Hz has a total internal impedance Zp of 127 ohm, referred to the primary side. Calculate the primary current if the secondary is accidentally short circuited.  (A) 43.5 A (B) 543 A (C) 9006 A (D) 721 A 

Last Answer : 543A

Description : The midrange frequency range of sound is from A. 256 to 2048 Hz B. 2048 to 4096 Hz C. 512 to 2048 Hz D. 16 to 64 Hz

Last Answer : A. 256 to 2048 Hz

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

Description : Coating thickness in case of galvanising of steel sheet generally corresponds to the deposition of __________ gms of zinc per m2 of steel strip. (A) 5-10 (B) 1000-1500 (C) 120-500 (D) 1500-3000

Last Answer : Option C

Description : Pick out the wrong conversion of absolute & kinematic viscosities. (A) 1 stoke = 1 cm2/sec (B) 1 N.sec/m2 = 10 paise (C) 1 stoke = 1 m2/sec (D) 1 m2/sec = 104 stokes

Last Answer : (C) 1 stoke = 1 m2/sec

Description : What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? A. 1.25 µsec B. 52 µsec C. 83.33 µsec D. 26 µsec

Last Answer : B. 52 µsec

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

Description : What sound intensity corresponds to a sound-intensity level of 50dB? A. 1 x 10-6W/m2 B. 1 x 10-7W/m2 C. 1 x 10-8W/m2 D.1 x 10-5W/m2

Last Answer : B. 1 x 10-7W/m2

Description : A compound bar consists of two bars of equal length. Steel bar cross-section is 3500 mm2 and that  of brass bar is 3000 mm2 . These are subjected to a compressive load 100,000 N. If Eb = 0.2  MN/mm2  and Eb = 0.1 ... 6 N/mm2 s  = 12 N/mm2 (D) b = 5 N/mm2 s  = 10 N/mm

Last Answer : (A) b = 10 N/mm2 s  = 20 N/mm

Description : The maximum delivery pressure of a reciprocating compressor may be about __________ kg/cm2 . (A) 1000 (B) 2000 (C) 3000 (D) 4000

Last Answer : (D) 4000

Description : If a steel rod of 20 mm diameter and 5 metres long elongates by 2.275 mm when subjected to an  axial pull of 3000 kg, the stress developed, is  (A) 9.5541 kg/cm2 (B) 95.541 kg/cm2 (C) 955.41 kg/cm2 (D) 9554.1 kg/cm

Last Answer : (C) 955.41 kg/cm2

Description : If a steel rod of 20 mm diameter and 5 metres long elongates by 2.275 mm when subjected to an  axial pull of 3000 kg, the stress developed, is  (A) 9.5541 kg/cm2 (B) 95.541 kg/cm2 (C) 955.41 kg/cm2 (D) 9554.1 kg/cm

Last Answer : (C) 955.41 kg/cm2

Description : An R.C.C. beam of 25 cm width and 50 cm effective depth has a clear span of 6 metres and carries a U.D.L. of 3000 kg/m inclusive of its self weight. If the lever arm constant for the section is 0.865, the maximum intensity ... , is (A) 8.3 kg/cm2 (B) 7.6 kg/cm2 (C) 21.5 kg/cm2 (D) 11.4 kg/cm2

Last Answer : Answer: Option A

Description : . One stoke (unit of kinematic viscosity) is equivalent to (A) 1 cm2 /second (B) 1 m2 /second (C) 1 gm/cm. second (D) 1 kg. m/second

Last Answer : (A) 1 cm2 /second

Description : One poise (unit of absolute/dynamic viscosity) is equivalent to one (A) gm/cm2 . sec (B) gm/cm. sec (C) cm2 /sec (D) m2 /sec

Last Answer : (B) gm/cm. sec

Description : Stress may be expressed in Newtons  (A) Per millimetre square (N/mm2 )  (B) Per centimetre square (N/cm2 )  (C) Per metre square (N/m2 )  (D) None of these 

Last Answer : (A) Per millimetre square (N/mm2 )

Description : When the clearance above the obstruction is equal to the radii of even Fresnel zone at the point of reflection the RSL A. remains the same B. is above threshold C. is decreased D. is increased

Last Answer : C. is decreased

Description : What is the photon energy for an infrared wave with frequency of 1012 Hz? a. 10.6 x 1034 joules b. 6.63 x 10-34 joules c. 6.63 x 10-22 joules d. 10.6 x 1022 joules

Last Answer : c. 6.63 x 10-22 joules

Description : What frequency is 10 octaves above 30 Hz? A. 30.72 kHz B. 30 kHz C. 300 Hz D. 307.2 kHz

Last Answer : A. 30.72 kHz

Description : Ten signals, each requiring 3000 Hz, are multiplexed on to a single channel using FDM. How much minimum bandwidth is required for the multiplexed channel ? Assume that the guard bands are 300 Hz wide. (A) 30,000 (B) 32,700 (C) 33,000 (D) None of the above

Last Answer : (B) 32,700

Description : Atmospheric noise becomes less severe at frequencies A. above 30 MHz B. below 30 MHz C. above 3000 kHz D. below 3000kHz

Last Answer : A. above 30 MHz

Description : What is the approximate single-hop nighttime range of F2 layer? A. 3840 km B. 3000 km C. 4130 km D. 2350 km

Last Answer : C. 4130 km

Description : The approximate single-hop nighttime range of F2 layer is ____. A. 3000 km B. 3840 km C. 4130 km D. 2350km

Last Answer : C. 4130 km

Description : The band of frequencies least susceptible to atmospheric noise and interference is: A. 30 – 300 kHz B. 300 – 3000 kHz C. 3 – 30 MHz D. 300 – 3000 MHz

Last Answer : D. 300 – 3000 MHz

Description : Maximum heat dissipation occurs from a steel wire (k = 0.5 W/m. k) of 15 mm diameter exposed to air (h = 20W/m2.k), when the insulation thickness is __________ mm. (A) 15 (B) 25 (C) 10 (D) 30

Last Answer : (B) 25

Description : Which one of the following units is used to measure intensity of noise? (A) decible (B) Hz (C) Phon (D) Watts/m2

Last Answer : (A) decible

Description : What is the capture area of a dipole operated at 75 MHz? A. 4 mm B. 2 m2 C. 2.088 m2 D. 4.088 m2

Last Answer : C. 2.088 m2

Description : For a clay slope of height of 10 m, the stability number is 0.05, = 2.0 t/m3 , C = 2.5 t/m2 , the critical height of the slope of the soil, is (A) 4.0 m (B) 12.5 m (C) 25.0 m (D) 15.0 m

Last Answer : (C) 25.0 m

Description : Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m and mass of 20 kg? A 12.32 Hz B 4.10 Hz C 6.16 HzD None of the above

Last Answer : C 6.16 Hz

Description : Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m and mass of 20 kg? A. 12.32 Hz B. 4.10 Hz C. 6.16 Hz D. None of the above

Last Answer : C. 6.16 Hz

Description : Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m and mass of 20 kg? A) 12.32 Hz B) 4.10 Hz C) 6.16 Hz D) None of the above

Last Answer : C) 6.16 Hz

Description : Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m and mass of 20 kg? C ( A )12.32 Hz (B) 4.10 Hz ( C )6.16 Hz (D)None of the above

Last Answer : ( C )6.16 Hz

Description : Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m mass of 20 kg? a. 12.32 Hz b. 4.10 Hz c. 6.16 Hz d. None of the above

Last Answer : c. 6.16 Hz

Description : Human ear is most sensitive to noise in the following frequency ranges: (A) 1-2 KHz (B) 100-500 Hz (C) 10-12 KHz (D) 13-16 KHz

Last Answer : (A) 1-2 KHz

Description : A 8 metre long simply supported rectangular beam which carries a distributed load 45 kg/m. experiences a maximum fibre stress 160 kg/cm2 . If the moment of inertia of the beam is 640 cm4 , the overall depth of the beam is (A) 10 cm (B) 12 cm (C) 15 cm (D) 18 cm

Last Answer : (A) 10 cm

Description : If the average compressive strength is 4000 kg/cm2 and standard deviation is 500, the co-efficient of variation is (A) 10 % (B) 12.5 % (C) 15 % (D) 18.5%

Last Answer : Answer: Option B

Description : A simply supported beam 6 m long and of effective depth 50 cm, carries a uniformly distributed load 2400 kg/m including its self weight. If the lever arm factor is 0.85 and permissible tensile stress of steel is 1400 kg/cm2 ... area of steel required, is (A) 14 cm (B) 15 cm2 (C) 16 cm2 (D) 17 cm

Last Answer : Answer: Option C

Description : The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2 . The flux, when the element temperature is increased to 1000°C for the same furnace temperature is (A) 11.2 kW/m2 (B) 12.0 kW/m2 (C) 14.6 kW/m2 (D) 16.5 kW/m

Last Answer : (D) 16.5 kW/m2

Description : What is the level of audible sound and audibility ?

Last Answer : audible sound: The sound we hear is called audible sound. If the sound vibration is between 20 Hz and 20000 Hz then we hear it. The sound produced within this vibration range is called audible sound. ... can hear sounds generated within this range, sounds less than 20 Hz or more than 20000 Hz .

Description : What is the upper limit of a dog's audibility ?

Last Answer : 35000 Hz Dog auditory upper limit.

Last Answer : We can hear the sound when the number of vibrations per second is between 20Hz and 20,000Hz . This limit of vibration is called the limit of audibility.

Description : What is the range of human audibility?

Last Answer : The human ear can pick up sounds ranging between approximately20 Hz to 20,000 Hz.Hz is Hertz, and 1 Hertz = 1 cycle/second