2 (Total 25 marks) X = 1 for odd no. in the second last digit of student ID; X = 4 for zero or even no. in the second last digit of student ID) use = A 150-W metal halide lamp emits the following spectrum of radiant power: 8W at 450 - 500 nm; 1X.0 W at 500 - 550 nm; 18W at 550 - 600 nm; and 9.X W at 600nm - 650nm. It is housed in an opal spherical diffuser with a radius of 20 cm. The light output ratio of the diffuser is 0.8X. The diffuser is placed at 2.4 m vertically above the centre of a rectangular table with dimensions of 2m x 1.5m. The spectral efficiency for photopic vision is given by V(2) = sin'[(1 - 380)180/350], where 2 is in nm. The maximum luminous efficacy is taken to be 683 Im/W at 555 nm. (a) Evaluate the luminous efficacy of the diffuser. (6 marks) (b) Find the luminous intensity of the diffuser. (5 marks) (c) Calculate the luminance of the diffuser. (4 marks) (d) Find the MAXIMUM and MINIMUM horizontal illuminances on the table. (10 marks) Page 2 of 4