(2014?山西模拟)小明想测量电磁炉的实际功率和效率,首先小明观察了家中的电能表,看到电能表的表盘如

2025-05-05 01:10:03
推荐回答(1个)
回答1:

(1)电磁炉1min内消耗的电能:W1=

90revs
3000revs/(kW?h)
=0.03kW?h;
电磁炉的实际功率为:
P=
W1
t1
=
0.03×3.6×106J
1×60s
=1800W;
(2)电磁炉在烧水过程中吸收的热量:Q=cm△t=4.2×103J/(kg?℃)×3kg×(100℃-25℃)=9.45×105J;
则η=
Q
W
×100%=
9.45×105J
1800W×10×60s
×100%=87.5%.
答:(1)电磁炉的实际功率为1800W;
(2)电磁炉在烧水过程中的效率是87.5%.