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tranhuyentrang08032007
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Một bóng đèn có ghi 220V-100W, được mắc với hiệu điện thế 110V. Tính công suất của đèn

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Nguyễn Ngọc Minh Châu
2 tuần trước

Đáp án:

`P=25 \ W`

Giải thích các bước giải:

`U_{dm}=220 \ V`

`P_{dm}=100 \ W`

`U=110 \ V`

Điện trở của đèn là:

`R=\frac{U_{dm}^2}{P_{dm}}=\frac{220^2}{100}=484 \ (\Omega)`

Công suất của đèn là:

`P=\frac{U^2}{R}=\frac{110^2}{484}=25 \ (W)`

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