The lamp hot bath bully commonly used in family bathrooms can improve the air temperature in the lighting area through the thermal radiation of light bulbs. The Yuba in Xiaoming's bathroom is marked w

The lamp hot bath bully commonly used in family bathrooms can improve the air temperature in the lighting area through the thermal radiation of light bulbs. The Yuba in Xiaoming's bathroom is marked with four. Known: S=6m2? h=2.5m？ ρ= 1.2kg/m3 c = 1.0× 103j/(kg？ ℃)? P0=250W？ T = 25 minutes

Solution:

( 1)∑ρ= mV，

∴ The mass of air is m = ρ V =1.2kg/m3× 6m2× 2.5m =18kg;

(2) Heat absorbed by air:

Q suction = cm △ t =1.0×103j/(kg? ℃)× 18kg×(28℃- 13℃)= 2.7× 105j；

(3) the four bulbs work normally at the same time,

∴ The total power of the four lamps is P=250W×4= 1000W,

∫P = Wt，

∴∴ The electric energy consumed in ∴∴25min is W = Pt =1000 w× 25× 60s =1.5×106j,

The efficiency η=Q, w×100% = 2.7×105j1.5×106j×100% =18%.

Answer: (1) toilet air quality18 kg; ;

(2) The heat absorbed by toilet air is 2.7×105j; ;

(3) The heating efficiency of Yuba for bathroom air is 18%.