Two bulbs A and B are rated 100w-120v and 10w-120v. they are connected across a 120v source in parallel find the current in each bulb and which will consume more energy
Answers
GIVEN :-
⇒ Bulb A is rated as = 100 w - 120 v
⇒Bulbs B is rated as = 10 w - 120 v
⇒ Two bulbs are connected across a source in series of = 120 v
TO FIND :-
⇒ Which will consume more energy ?
SOLUTION :-
⇒ In the bulb A -
⇒ Volts = 120 v
⇒ Power = 100 w
⇒In the bulb B-
⇒ Volts = 120 v
⇒ Power = 10 w
Now let us find the resistance of the two bulbs -
⇒ R = V² / P
Let us find the resistance for the bulb A-
⇒ Bulb A ( R ) = 120 ² / 100 = 144 ohm
⇒ Bulb B ( r ) = 120 ² / 10 = 1440 ohm
Now we got the resistance for both the bulbs.
To find the series combination , we need to use the below formula to find out it -
⇒ R = R₁ + R₂ = 144 + 1440
= 1584 ohm is the resistance in series combination.
So 10 watts bulb consume more energy because uses less power and also the amount o current flowing is less . Remember the formula :- P=IxE.
Answer:
given:
bulb A is rated 100w-120v
bulb B is rated 10w-120v
required :Which bulb will consume more energy ?
solution : Let's find out the resistances of each bulb from the data given:
R1 = U1^2 /
⇒P1 = 120^2 / 100 = 144 Ohm
R2 = U2^2 / P2 = 120^2 / 10 = 1440 Ohm
Let's use P = I^2 * R for each bulb and find out if it is greater.
P1 = (120 / (144 + 1440))^2 * 144 = 0.8264 W
P2 = (120 / (144 + 1440))^2 * 1440 = 8.2644 W.
Answer: second bulb will consume more energy.
Explanation: