Solve the following problems: 1.Find the optimum reverberation time at 500 Hz of a living room 20 ft. long, 13 ft. wide and 8 ft. high with a plaster ceiling (α₁ = 0.02), a carpeted floor (α₂ = 0.30), a wood-paneled side wall (α₃ = 0.12), an opposite glass wall (α₄ = 0.03), an end wall of medium drapery (α₅ = 0.40), and a brick fireplace (α₆ = 0.02) for the other end wall, with no additional furnishings or occupants. 2.A lecture room 16m long, 12.5m wide and 5m high has a reverberation time of 0.75s. Calculate the average absorption coefficient of the surfaces using the Norris-Eyring’s formula.

Solve the following problems: 1.Find the optimum reverberation time at 500 Hz of a living room 20 ft. long, 13 ft. wide and 8 ft. high with a plaster ceiling (α₁ = 0.02), a carpeted floor (α₂ = 0.30), a wood-paneled side wall (α₃ = 0.12), an opposite glass wall (α₄ = 0.03), an end wall of medium drapery (α₅ = 0.40), and a brick fireplace (α₆ = 0.02) for the other end wall, with no additional furnishings or occupants. 2.A lecture room 16m long, 12.5m wide and 5m high has a reverberation time of 0.75s. Calculate the average absorption coefficient of the surfaces using the Norris-Eyring’s formula.