Register to reply 
Luminous flux problem 
Share this thread: 
#1
Jun2506, 02:14 PM

P: 421

Please help me with this problem.
# An isotropic point source of 100 candela is fastened to the ceiling of a room. What is the total luminous flux falling on all the walls and floor? I solved it in the following way: Here Luminous intensity(I) = 100 cd, Total solid angle(w) = 2 (pi) steradian Total luminous flux falling on all the walls and floor = I x w = 100 x 2(pi) = 100 x 2 x 3.14 = 628 lumens Is it right? 


#2
Jun2506, 07:11 PM

Sci Advisor
HW Helper
P: 6,683

AM 


#3
Jun2606, 02:38 AM

P: 421




#4
Jun2606, 05:27 AM

Emeritus
Sci Advisor
PF Gold
P: 9,772

Luminous flux problem



#5
Jun2606, 11:44 AM

P: 421

Solid angle(w) = Area of hemisphere/R^2 = [2(pi)R^2]/R^2 = 2(pi) steradians I think radian is a 2 dimensional unit whereas steradian is a 3 dimensional unit of angle. I may be wrong. 


#6
Jun2606, 07:22 PM

Sci Advisor
HW Helper
P: 6,683

AM 


#7
Jun2706, 01:13 AM

P: 421

That's ok. Thanks.



Register to reply 
Related Discussions  
Luminous intensity due to an isotropic point source of light  Advanced Physics Homework  1  
Luminous intensity in different directions  Introductory Physics Homework  4  
Calculation of Luminous flux  Advanced Physics Homework  0  
Luminous Object in the Gulf of Venezuela  General Discussion  0  
Rare transient luminous event photographed in upper atmosphere  Biology  1 