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# If two different wattage lamp connected in series which lamp will glow brighter and why?

Updated: 8/10/2023 Wiki User

8y ago

I was also searching for the same but according to me the lamps with higher wattage should glow brighter. We know that, P=VI In series connection current is same through all the lamps but voltage across each lamp depends on the wattage of the bulb. So the bulb with higher wattage will draw more voltage and glow brighter.

Unfortunately, the previous answer is incorrect, although it seems* to be the logical answer! The higher-wattage lamp has a lower resistance than the lower-wattage lamp. So, when they are connected in series, the larger voltage drop (IR)will appear across the lower-wattage lamp. As power is proportional to the square of the voltage, it is the lower-wattage lamp that will be the brighter.

[*Many people have the mistaken belief that a higher-wattage lamp has a higher resistance than a lower-wattage lamp. That's the wrong way around!] Wiki User

8y ago   Wiki User

11y ago

Because the filament of a 40-W lamp has a higher resistance than that of a 60-W lamp and, therefore, will experience a greater voltage drop -the lamp with the voltage drop closer to its rated voltage (in this case, the 40-W lamp) will be the brighter.   Wiki User

12y ago

The manufacturers of light bulbs want to give their customers light. This requires the use of energy (Watts) which cost money for their use. Manufacturers design their light sources so that users get as much light as possible from the bulb for a given wattage while maintaining a reasonable lifetime (otherwise we would just get flash bulbs).   Wiki User

10y ago

it is because watts is the same thing as joules per second. That is how much energy can be done in a second (the unit of time). A 60 watt bulb releases 60J energy in one second where as a 25 watt bulb releases 25J in one second Hope this helps😄   Wiki User

13y ago

The conservation of energy means energy isn't created or destroyed. So the energy you put in is equal to the energy you get out (but it may be transformed into different types of energy).

Electrical energy (or power) is measured in Watts, where 1 watt second = 1 joule. A watt is equal to the voltage applied times the current (ignoring any phase shift due to inductance and capacitance of the circuit, a valid assumption for your case).

If you measure the voltage and current under your two situations (series and parallel), you will notice that the current changes, but the voltage will remain constant. Specifically, the current will increase (by a factor of four if the light bulbs are the same) in the parallel circuit compared to the series circuit.

Conservation of energy is not violated specifically because more energy is pumped into the parallel circuit, which then produces more light and heat; the amount of light and heat produced will be 4 times more in the parallel circuit compared to the series circuit.

The reason 4 times: Take the resistance of the light bulb to be R, then the resistance of two light bulbs in series is R+R = 2R; the resistance of two light bulbs in parallel is:

R*R/(R+R) = R/2. Using Ohm's law, I = V/R, it is evident that 4 times more current (and thus four times more power) will be flowing to the parallel circuit.   Wiki User

11y ago

The filaments in the bulb are larger and draw more electricity. The bulbs also get hotter if you will notice.

The filament in a higher wattage bulb is actually smaller than a lower wattage bulb. The smaller filament has less resistance which allows for more current to flow. More current, more heat, more light.   Wiki User

12y ago

two lamps in parallal will be brighter.

It depends entirely on the voltage/power ratings of the two lamps.   Wiki User

11y ago

A lamp will only operate at its rated power if it is subject to its rated voltage (both values are printed on a lamp). It follows, then, that the lower the voltage you apply to a lamp the dimmer it will become.

When lamps are connected in series, a voltage drop will appear across each lamp (Kirchhoff's Voltage Law), and this voltage drop is the product of the current flowing through it and the resistance of its filament. As more powerful lamps have a lower resistance than less powerful lamps, the voltage drop across a more powerful lamp will be lower than the voltage drop across a less powerful lamp. So, when different lamps are connected in series, the less powerful lamps will have greater voltage drops across them, and will operate brighter than the more powerful lamps. ALL the lamps will illuminate at about the same time (depending how long it takes for their filaments to heat up) because the same current flows through them at the same time.   Wiki User

13y ago

the 40 watt bulb will glow brighter in series because it will consume less power.   Wiki User

13y ago

A: A BULB in parallel has available all the power that the source can supply. In series the power divide according to each bulb resistance.   Earn +20 pts
Q: If two different wattage lamp connected in series which lamp will glow brighter and why?
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Still have questions?  Related questions

### Three bulbs of different watts are connected in series - which bulb will burn brightly - the higher wattage bulb or the lower?

lower wattage bulb

### When resistors are connected in series then what happens to the watt?

Resistors are rated in wattage so the lowest wattage rating will be the wattage of the series circuit. It will be able to handle that power any more and the lowest wattage resistor could be damaged and fail.Another AnswerWhen two or more resistors are connected in series, the resistor with the lowest resistance will operate at the highest power. If the power developed by a resistor exceeds its rated power, then the resistor may burn out.

### Does the number of batteries change the brightness of the bulb?

It will if the batteries are connected in series. If they are connected in parallel, the lamp will burn longer, but not brighter.

### Connected in series or parallel will each bulb glow brighter?

In parallel, each bulb will have full voltage applied across them. However, in series, the voltage across each bulb won't be the same as supply voltage. Thereby, bulbs connected in parallel will glow brighter.

### What happens to a light bulb in series?

If you put two incandescent bulbs of the same wattage in series, they will both light with the same intensity. If one is lower wattage than the other, the lower wattage bulb will light brighter than the oter one. If you put two 115 volt bulbs of the same wattage in series across 230 volts, both will light equally, but if you use dissimilar wattages, the smaller one will burn out.

### What type of circuit will produce brighter lights is it series circular direct or parallel?

Parallel connections will draw more current than equivalent lights connected in series, so the parallel configuration will be brighter.

Current.

### For bulbs connected in series the high watt bulb has high resistance?

No, the highest wattage bulb will have the lowest resistance.

### Light bulb in parallel circuit brightness?

Two bulbs connected in parallel are brighter than two connected in series. The resistance of the circuit is lower, electrons can flow more easily.

### What will happen when two resistors with different wattage rating will be connected series?

Resistance wise, the rated wattages are immaterial. When calculating the amount of power the two of them would be able to dissipate, (or the maximum current) you would have to use V=IR and P=VI to work out which resistor would run into it's wattage rating first.

### If you have two 5 watt bulbs connected in series and then in parallel which circuit arrangement will give you brighter bulbs explain your answer?

Brighter in parallel. In series the voltage is divided between the two bulbs, thus the current will only be half so that the power of each bulb will only be one quarter (of 5 watts) in the series set-up.

### A 40W bulb or a 60W bulb will glow more brighter if connected in series?

The 40-W lamp will be the brighter, because it has a greater resistance that the 60-W lamp and, therefore, will experience a greater voltage drop across its terminals. The closer the voltage drop is to the lamp's rated voltage, the brighter it will be.