A very small sample of an opaque surface is initially at 1200 K and has the spectral, hemispherical absorptivity shown The sample is placed inside a very large enclosure whose walls has an emissivity of 0 2 and is maintained at 2400 K (a) What is the total, hemispherical absorptivity of the sample surface (b) What is its total, hemispherical emissivity (c) What are the values of the absorptivity and emissivity after the sample has been in the enclosure a long time (d) For a 10 mm diameter spherical sample in an evacuated enclosure, compute and plot the variation of the sample temperature with time, as it is heated from its initial temperature of 1200 K 0 8 0 1 2

Question: A very small sample of an opaque surface is initially at 1200 K and has the spectral, hemispherical absorptivity shown. The sample is placed inside

A very small sample of an opaque surface is initially at 1200 K and has the spectral, hemispherical absorptivity shown. The sample is placed inside a very large enclosure whose walls has an emissivity of 0.2 and is maintained at 2400 K.

(a) What is the total, hemispherical absorptivity of the sample surface?

(b) What is its total, hemispherical emissivity?

(d) For a 10-mm-diameter spherical sample in an evacuated enclosure, compute and plot the variation of the sample temperature with time, as it is heated from its initial temperature of 1200 K.

0.8 0.1 2

Step by Step Solution

★★★★★

3.46 Rating (162 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer

Step: 1 Unlock

KNOWN Small opaque surface initially at 1200 K with prescribed a distribution placed in a large enclosure at 2400 K FIND a Total hemispherical absorpt... View full answer

Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock

Step: 3 Unlock

Document Format (1 attachment)

8-E-M-E-H-M-T (1171).docx

120 KBs Word File

Students Have Also Explored These Related Mechanical Engineering Questions!

The spectral emissivity function of an opaque surface at 1000 K is approximated as Determine the average emissivity of the surface and the rate of radiation emission from the surface, in W/m 2 . '...

The spectral, hemispherical absorptivity of an opaque surface is as shown. What is the solar absorptivity, ?S? If it is assumed that ?? = ?? and that the surface is at a temperature of 340 K. what is...

The spectral absorptivity of an opaque surface is as shown on the graph. Determine the absorptivity of the surface for radiation emitted by a source at (a) 1000 K (b) 3000 K. 0.8 0.1 2, um 0.3 1.2

5-180 Determine the power input for a compressor that compresses helium from 150 kPa and 20C to 400 kPa and 200C. Helium enters this compressor through a 0.1-m2 pipe at a velocity of 15 m/s. 5-181...

What operational changes would you recommend to Wally to improve performance? Wally Meyer deftly balanced his office keys and a large printout of forecasting data as he wheeled his mountain bike...

I have attached the case study and the rubric for this. can I get help here to organzie an answer? CATERPILLAR, INC: THE IMPACT OF DECISION BIASES AND RISK ON CAPITAL BUDGETING Timothy D. West...

There are two problems due this week (each worth 35 points) as follows. Problem 1.6 (page 20) In comprehensive paragraphs, answerrequirements a to e. You will have 5 paragraphs total of four to five...

Write a literature review for your study. See below for an example of a literature review. Your literature review should provide both analysis and synthesis of previous studies as related to the...

For example, when a ball is thrown into the air, it gains kinetic energy as it moves upward. As it reaches the top of its trajectory, this kinetic energy is converted into potential energy. When the...

This means that there is no preferred frame of reference in the universe, and the laws of physics are the same regardless of where an observer is located. This principle has been confirmed by...

Name a pokayoke device that was built into your car.

(a) Calculate Kp for this reaction at 500.0 K. (b) If the vessel has a volume of 5.00 L, calculate Kc at this temperature?

Aggregate demand in Canada increases if a) China buys more Canadian oil. b) aggregate demand in India decreases. c) Canada buys more Porsches from Germany. d) the value of the Canadian dollar...

Refer to the preceding common information for Paulcrafts acquisition of Switzers common stock. Assume that Paulcraft pays $440,000 for 80% of Switzer common stock. Paulcraft uses the simple equity...

Exquisite Jewelers is developing its annual financial statements for 2015. The following amounts were correct at December 31, 2015: cash, $58,000; accounts receivable, $71,000; merchandise inventory....

Romero issues $ 3,400,000 of 10%, 10- year bonds dated January 1, 2013, that pay interest semiannually on June 30 and December 31. The bonds are issued at a price of $ 3,010,000. Required 1. Prepare...

Flagstaff Systems issues bonds dated January 1, 2017, that pay interest semiannually on June 30 and December 31. The bonds have a $90,000 par value and an annual contract rate of 12%, and they mature...

Warner Co. entered into the following transactions involving short-term liabilities in 2012 and 2013. 2012 Apr. 22 Purchased $ 5,000 of merchandise on credit from Fox Products, terms are 1/10, n/30....

Use Lewis symbols to predict the formula for the compound that forms between calcium and chlorine.

Consider a double-pane window whose air space width is 20 mm. Now a thin polyester film is used to divide the air space into two 10-mm-wide layers. How will the film affect (a) Convection (b)...

In an ordinary double-pane window, about half of the heat transfer is by radiation. Describe a practical way of reducing the radiation component of heat transfer.

Consider three similar double-pane windows with air gap widths of 5, 10, and 20 mm. For which case will the heat transfer through the window will be a minimum?

Which of the following is not a transactions account? Question 6 options: A ) A checking account. B ) A share draft account. C ) A savings account. D ) A NOW account.

Bob's Discount Shoe Source is adding a new line of shoes to the company portfolio and has the following information: the expected market return is 13%, the risk-free rate is 3%, and the expected...

1. A sample of n=30 bags of Nestle's Raisinets were analyzed in August of 2012 by a Baruch class. The net weights in grams of the 30 bags are given, below. The data can be readily copied into Excel....