Question

Explain with proper calculations which lamp glows the brightest?in parallel
​

Answer 1

The most confusing question we received that if two bulbs are connected in series and then in parallel, which one will glow brighter and what are the exact reasons? Well, there are lots of info around the web, but we will go in a very step by step details to calculate the exact values to clear the confusion.

First of all, keep in mind that the bulb having a high resistance and dissipate more power in the circuit (no matter series or parallel) will glow brighter. In other words, the brightness of the bulb depends on voltage, current (V x I = Power) as well as resistance.

Also, keep in mind that power dissipated in Watts is not the unit of brightness. Unit of brightness is lumens (denoted by lm which is SI derived unit of luminous flux) also known as candela (base unit of luminous intensity). But the light brightness is directly proportional to the bulb wattage. That’s why the more wattage a bulb is using will glow brighter.

Answer 2

From the calculation and analysis we can say that , 1st Lamp glow the brightest.

Explanation for the answer:

We know,

The lamp which will have the lowest resistance ,will get the most current due to this it will glow the brightest.

To calculate the resistance ,

R = V / I  (Ohm's law)

Here

R= Resistance ,

V= Voltage  

I= Current flowing.

Consider, lamps are identical ,voltage drop of 100V.

And it has resistances,

20 ohms, 25 ohms, 50 ohms

Now  from the ohm's law,

I = V / R

For 1st lamp,

I = 100V / 20 ohms

 = 5A

For 2nd lamp,

I = 100V /25ohms

 =4A

For 3rd lamp,

I = 100V / 50 ohms

 = 2A

From the calculation and analysis we can say that , 1st Lamp glow the brightest.

#SPJ3