(b) The reverberation time of a hall is Twhen an object made of certain material is placed inside a hall. However, the reverberation time increases to T2 on removing the object from the hall. Obtain an expression of the absorption coefficient of the material used in the object, where the total surface area of the hall is A and it's volume is V. The surface area of the object is Ao. Use meter as the unit of length.

(b) The reverberation time of a hall is Twhen an object made of certain material is placed inside a hall. However, the reverberation time increases to T2 on removing the object from the hall. Obtain an expression of the absorption coefficient of the material used in the object, where the total surface area of the hall is A and it's volume is V. The surface area of the object is Ao. Use meter as the unit of length.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.1P: Consider a flat plate or a plane wall with a thickness L and a long cylinder of radius r0. Both of...

See similar textbooks

Similar questions

11. Athermally insulated battery is being discharged at atmospheric pressure and constant volume. During a 1 hour test it is found that a current of 50 A and 2 V flows while the temperature increases from 20°C to 32.5°C. Find the change in internal energy of the cell during the period of operation. [Ans.-36 x 104 J]
Determine the reverberation time of a room whose dimensions L=20m, W=13m, and H=8m with a triangular ceiling of height 2m. The wall is made of marble with absorption coefficient of 0.03, the floor is covered with carpet (13m X 13m) with an absorption coefficient of 0.4, the ceiling is covered with plaster and lathe having 0.70 absorption coefficient. The floor is tiled with an absorption coefficient of 0.4. The sliding window on both sides is open half with a dimension of 2m X 10m and 0.075 absorption coefficient. The door (1.8m X 0.7m) has an absorption coefficient of 0.01. The windows is covered with blinds having 0.5 absorption coefficient half roll upward. A window type air-condition unit (W=470mm, H=340mm, D=600mm) is mounted at one side wall 6.5m from the floor to the base of the ACU with absorption coefficient of 0.35 and a refrigerator with dimensions 2ft X 2ft X 7ft is present in the room with 0.15 absorption coefficient. Use Fitzroy Equation.
(i) Find the thickness of an isolated block in ‘meter’ capable of being charged to 2.4 x 106Volt potential before sparking into the air, given that dielectric strength of air is 24,000V/cm. (ii) Find the heat energy(flow) in ‘Joules’ required to prepare a coffee in an electric kettlewith 0.5 litre (1litre = 10-3 m3) of water which is heated from 30ºC to 85ºC?Take density of water as 1000 kg /m3and Specific heat of water as 4.187 kJ/kg º K.
In last week's assignment, you calculated mean free path, total absorption, and reverberation time for a room that is 4 m long, 7 m wide, and has a ceiling height of 3 m. The floor is hardwood, = .15 at 500 Hz. The walls are gypsum wallboard (GWB), = .30 at 500 Hz. The ceiling is acoustic ceiling tile (ACT), = .95 at 500 Hz. 1) What is the room constant for this room?
In an electrical discharge machining process, the breakdown voltage across inter electrode gap (IEG) is 200 V and the capacitance of the RC circuit is 50 μF. The energy (in J) released per spark across the IEG is T
: A 100-Ω platinum RTD is being used to measure temperature in an oven. The present temperature is 130 Ω, find the corresponding temperature.
The source sent an ultrasonic signal of the frequency of 5 MHz and received two echo-signals with a delay of 60 ms between them. The first echo-signal returned after 40 ms. What is the thickness of the organ from which the signal was reflected if the reflection occurred from opposite sides of the organ? What is the absorption coefficient if the intensities of the echo-signals differ by 1120 times? The speed of the wave is 1450 m / s.
A 250 kg weight is hanging from the ceiling bya thin copper wire. In its fundamental mode, this wire vibrates at thefrequency of concert A (440 Hz). You then increase the temperature ofthe wire by 40 C°. (a) By how much will the fundamental frequencychange? Will it increase or decrease? (b) By what percentage will thespeed of a wave on the wire change? (c) By what percentage willthe wavelength of the fundamental standing wave change? Will it increaseor decrease?
220 Spring-2021_Exam-1 e/1FAlpQLSftrtW9fq5KycKNGGYjhaDgooyDJ9tkegtHokh0ZKa4zlaQug/formResponse G ww - Google Search 0.047 kg 0.019 kg 0.040 kg 0.031 kg The wavefunction of a mechanical wave on a string is described by: y(x.t) = 0.012sin(tx-100tt+2t/3), where x and y are in meters and t is in seconds. The transverse velocity of an element on the string at the left end (x = 0), at time t = 0 is: O #0.6x3m m/s None of the listed +0.6 m/s endulum theratio of the maximum angular langular veldoity Ə'max, is 2S(-1). What is comblete twotoscillations? Han oscillatory mot on acce eration
Figure 3 shows cross section of a duct. If each wall is 100 cm, surface C is insulated, and duct is very long. Evaluate; a) net radiation per meter of duct for surface A, b) temperature of surface C, and c) effect of changing in the value of ɛ, on the results. C,T3, ɛ3 = 0.8 Figure 3 B,T2 = 700 K, ɛ2 = 0.5 A,T, = 1000 K,ɛ, = 0.33
Fourier rate equation predicts that the temperature difference is not inversely proportional to the cross- sectional area. Select one: O a. False O b. True
30_ Select the correct statement for a radial conductivity exp Select one: a. The mid outer surface represent the heating area while the side surface represent the cooling area b. None of them is true c. The outer section represent the heating area and the inner section represent the cooling area d. The inner section represent the heating area and the outer section represent the cooling area 24_ The device with highest static head loss is Select one: a. No static head loss in this experiment b. Venturi meter c. Orifice plan d. Rotameter 26_ If surface is not leveled under the center of pressure tank Select one: a. Legs of the device can be rotated to create level surface b. Items should be added under the device to create level surface c. The device has and auto leveling d. none