Two light bulbs have constant resistances of 400 Ω and

fertilizeki

fertilizeki

Answered question

2021-12-30

Two light bulbs have constant resistances of 400 Ω and 800 Ω. If the two light bulbs are connected in series across a 120 V line, find the power dissipated in each bulb

Answer & Explanation

Esta Hurtado

Esta Hurtado

Beginner2021-12-31Added 39 answers

Given: 
The resistance across first bulb is R1=400Ω 
The resistance across second bulb is R2=800Ω 
The voltage across the builbs is V=120 V
The formula to calculate the power dissipated in first bulb is, 
P1=V2R1 
Here, P1 is the power dissipated in first bulb, V is the voltage and R1 is the resistance across first bulb. 
Substitute the khown values in the formula to calculate the power dissipated in first bulb. 
P1=(120 V)2400Ω(1 W1 V2/Ω)
=36 W
The formula to calculate the power dissipated in second bulb is,
P2=V2R2
Here, P2 is the power dissipated in first bulb and R2 is the resistance across second bulb.
Substitute the known values in the formula to calculate the power dissipated in second bulb.
P2=(120 V)2800Ω(1 W1V2/Ω)
=18 W
Thus, the power dissipated in first bulb is 36 W and the power dissipated in second bulb is 18 W.

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