2007-02-05 03:32:06 · 8 answers · asked by sriramna 1 in Science & Mathematics ➔ Physics
The power ratings,( P), 60 W and 40 W are for the usual line voltage, ~ 220 V in India.
Since P = VI = I.I.R and R = V/I, for usual voltage (the bulbs are then connected in parallel). The voltage is the same for different bulbs, P is proportional to I. Then, I (60) > I(40) and R(60) < R(40).
When connected in series, the current will be same in both but voltage will be different. P is proportional to R.
So the 40-watt bulb having higher R, will have more power and hence shine brighter. .
2007-02-05 04:14:24 · answer #1 · answered by Entho 2 · 1⤊ 2⤋
The 40 watt bulb because it has less resistance probably the 60 watt would not even glow.Because the 60 watt would be getting only 40 volts and the 40 watt would be getting 60 volts.you could go by the percent method and see how much percent it will burn but i wont go there. you just asked which one would be brighter. I apoligize i meant more resistance on the 40 watt bulb got confused tryng to do the math lol.
2007-02-05 03:49:20 · answer #2 · answered by Ernest B 2 · 0⤊ 0⤋
The 40 watt bulb.
2007-02-05 03:35:48 · answer #3 · answered by Voice of Insanity 5 · 0⤊ 0⤋
floodtl was almost there
the key is that bulbs are rated at a power for a given voltage, but when connected in series what is known is that they are carrying the same current
the 60 W bulb *must* have a lower resistance - he did his sums wrong
so the 40 W bulb will be brighter for the same current (W = I^2 R, and I is the same).
in serise
2007-02-05 03:54:17 · answer #4 · answered by Anonymous · 1⤊ 1⤋
60 watt is brighter in series. In parallel they would both have the same brightness.
2007-02-05 03:44:58 · answer #5 · answered by maimatt7 3 · 0⤊ 1⤋
no matter if the resistance of two bulbs is an similar the single placed 2d in series received't glow as brightly because the first. even as in parallel the voltage throughout them is equivalent although in series they don't seem. If the 40w bulb is placed first that is going to take its 40w of allotment . If the skill accessible isn't tremendous adequate then the 2d bulb on your case the 60w will in common words shine as bright because the last skill will enable it to finish that.
2016-11-25 03:51:19 · answer #6 · answered by ? 3 · 0⤊ 0⤋
P = V^2/R, so R= V^2/P
60 = 14400/240
40 = 14400/360
I = E/R = 120/600= .2a
I = 120/600 = 0.205a
E60 = IxR = .2 x 240 = 120
E40 = .205 x 360 = 73.8
Huh. I would have sworn the 40W would have been brighter. But then, math was never my strong suite.
Edit: D'OH!!! Like I said!
2007-02-05 04:15:08 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Your electricity bill !
LOL
btw it wud be 60watts anyway either in serial or parallel.
2007-02-05 03:41:48 · answer #8 · answered by Anonymous · 0⤊ 1⤋