Question

PRINTER VERSION « BACK NEXT Chapter 24, Problem 33 A heat lamp emits infrared radiation whose rms electric field is Erms - 3900 N/C. (a) What is the average Intensity of the radiation? (b) The radiation is focused on a person's leg over a circular area of radius 4.4 cm. What is the average power delivered to the leg? (c) The portion of the leg being Irradiated has a mass of 0.32 kg and a specific heat capacity of 3500 J/(kg.Cº). How long does it take to raise its temperature by 3.0 C°? Assume that there is no other heat transfer into or out of the portion of the leg being heated. Units (a) Number (b) Number Units (c) Number Units Click If you would like to Show Work for this question: Open Show Work By accessing this Question Assistance, you will learn while you earn points based on the Point Potential Policy set by your instructor. SUBMIT ANSWER Question Attempts: 0 of 2 used SAVE FOR LATER % Earn Maximum Points available only if you answer this question correctly in your first attempt Next → 47768N10050 MacBook Pro DII DD

Answer 1

Firen: - Erms = 3900 N/C radius of arular area - 4.4cm mass m = 0.32 kg specific heat capacity C = 3500 J/kg °C AT = 3.0 °C a N m2 2 2 cto Erms is The average indenstly at indou oed oodiafton is (3x 108 m/s) ( 8,85 x 16'2 (2 x (3900 N/C) 2 8= 4.088 x 104 W/m2 b) The average power delivered to the leg P = B A B (782) = (4.038 x 104 W/m²) XX X (4.4x162)2 = 2.456 x 102 haft combining the alations The time required to scise the tempuratare Q = GMAT by 3.0°C Comat (3500 J/kg°c) X10.32. Kg) x 3.0°C Р 2.4568 102 Kalts, and t = ole С. = t = pa t= 13.68 sec