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Physics electric circuit mygod
圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013040322...
I want to ask under this condition, the total current decreases so the current passes through the bulb decreases.
At the same time, due to internal resistance, voltage across light bulb increases.
The answer said the bulb becomes brighter.
However I don't understand since the current decreases and voltage increases, how do we know the bulb becomes brighter?
Thanks for your help!!!!!!!!!!!!!!!!!!!!! >O<
tsz******
what are you saying? I don't understand.
2 個解答
- 天同Lv 78 年前最愛解答
The total current decreases but the current passes through the light bulb increases.
Because the resistance of the rheostat has increased, this forces more current to pass through the bulb than before (in a parallel arrangement, current tends to flow through the branch with small resistance). As a result, the current through the bulb becomes larger despite the decrease of the main current.
In the actual fact, this follows naturally from the increase in p.d. across the bulb. A higher p.d. drves more current to flow through the bulb than before.
- 8 年前
O(a light bulb)+_____-O(a light bulb)+____-O(a light bulb)O(a light bulb)
資料來源： me this J6 guy
