if 100W and 200W bulbs are connected in series to a supply
which bulb will glow brighter and why

Answers were Sorted based on User's Feedback



if 100W and 200W bulbs are connected in series to a supply which bulb will glow brighter and why ..

Answer / neeraj

100W bulb will glow brighter.
Suppose they are first connected individually (to find their
resistance), we will find that resistance R=V^2/P will be
higher for 100W bulb.
Now, when two bulbs are connected in series, current through
each of them is same so the thermal energy produced per
second i.e. I^2.R will be higher for 100W bulb which
accounts for its high brightness.

Is This Answer Correct ?    55 Yes 6 No

if 100W and 200W bulbs are connected in series to a supply which bulb will glow brighter and why ..

Answer / chaturbhuj poddar

If the rating of two bulbs be as (100W-220V) &(200W-220V)and be connected in series to the same d.c.voltage supply. then the value of current is same in both the bulbs. It can be seen that the resistance of 100W bulb is greater than the resistance of the 200W bulb. Hence, heat produced in 100W bulb is more than produced in 200W.Conclusion: 100W will glow brighter than 200W bulb.

Is This Answer Correct ?    33 Yes 9 No

if 100W and 200W bulbs are connected in series to a supply which bulb will glow brighter and why ..

Answer / guest

100w because resistance will be higher

Is This Answer Correct ?    6 Yes 6 No

if 100W and 200W bulbs are connected in series to a supply which bulb will glow brighter and why ..

Answer / chaturbhuj poddar

Let us suppose that the first bulbs is marked as 100W-200V and the second bulb as 200W-200V, and both are connected in series to 200V d.c. supply to make easy calculation.
Resistance of 100W bulb R1 = V^2/P = 200*200/100 = 400 ohm,
Resistance of 200W bulb R2 = V^2/200 = 200*200/200 =200 ohm
Thus, Resistance of the combination = =600 ohm. current through each bulb = V/600= 200/600 =1/3 A
Heat produced by 100W bulb per second H1=I^2*R1=(1/9)*200J/sec
Heat produced by 200W bulb per second H2=(1/9)*400 J/s.
H2 is greater than H1. Thus, 200W bulb will glow brighter.

Is This Answer Correct ?    14 Yes 38 No

if 100W and 200W bulbs are connected in series to a supply which bulb will glow brighter and why ..

Answer / l.shanmugam

* both are bulbs same bright
* if the bulb are series conection power supply same as
series conection so both are bulbs same bright

Is This Answer Correct ?    7 Yes 38 No

Post New Answer

More General Physics Interview Questions

Two bulbs, one of 600W and the other of 100W having same voltage rating are connected in series across the supply in a room.Which bulb will glow brighter? If one of the bulb is switched off, what will be effect on illumination?

2 Answers  


Which lens is used for correcting long ?sightedness ?

1 Answers  


What is radium used for?

0 Answers  


How do you find the refractive index of a liquid by using total internal reflection?

0 Answers  


How much oxygen is in the atmosphere?

0 Answers  






How fast can a shadow move ? If a moth fly's in front of a very bright room temperature light powerful enough to light up Saturn like the sun could it's shadow move faster then light if there was no light diffusion.

0 Answers   ME,


What is photometry?

0 Answers  


how physics help in banking?

2 Answers   Banking, Indian Overseas Bank, Punjab National Bank, UCBL,


Tell me what path does an asteroid take?

0 Answers  


what law yields an equation that is used in determining crystal structure from interference patterns produced by monochromatic x-rays?

0 Answers  


what is the principle used in electromagnetic spectrum?and why there is a necessary of having an electron with unpaired spins?and how the uncertainity principle is used to determine the frequency of an spectral lines ?

0 Answers  


What is the difference between optical zoom, digital zoom and smart zoom?

0 Answers  


Categories