解题思路:
电能表上标着“
600
revs
/(
kW
⋅
h
)
,表示的是电路中每消耗
1
kW
⋅
h
的电能,电能表的转盘转
600
r
,所以转盘转动
30
转消耗电能:
W
=
kW
⋅
h
=
0.05
kW
⋅
h
=
"
1.8
×
10
"
5
J
,转
30
转所用时间为
t
=
5
min
=
5
×
60
s
=
300
s
,所以用电器的功率:
P
=
=
=
600
W
=
0.6
kW
.
答案选
D
D
<>
解题思路:
电能表上标着“
600
revs
/(
kW
⋅
h
)
,表示的是电路中每消耗
1
kW
⋅
h
的电能,电能表的转盘转
600
r
,所以转盘转动
30
转消耗电能:
W
=
kW
⋅
h
=
0.05
kW
⋅
h
=
"
1.8
×
10
"
5
J
,转
30
转所用时间为
t
=
5
min
=
5
×
60
s
=
300
s
,所以用电器的功率:
P
=
=
=
600
W
=
0.6
kW
.
答案选
D
D
<>