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Question
In an electrical circuit three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness?
Options
Brightness of all the bulbs will be the same
Brightness of bulb A will be the maximum
Brightness of bulb B will be more than that of A
Brightness of bulb C will be less than that of B
Solution
Brightness of bulb B will be more than that of A
Explanation -
Since all the three bulbs are connected in parallel so potential difference (V) across all the bulbs is same. Power dissipated is given by
`"P" = "V"^2/"R"`
Lower the resistance, higher the power dissipation. Hence higher the brightness.
Out of all the three bulbs, 100 W bulb will have minimum resistance because rated voltage of all the bulbs will be same and its power dissipation is maximum.
Thus, 100 W will have maximum brightness and 40 W bulb will have minimum brightness.
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