Question
Question: If a 30 V, 90 W bulb is to be worked on a 120 V line, a resistance of how many ohms should be connec...
If a 30 V, 90 W bulb is to be worked on a 120 V line, a resistance of how many ohms should be connected in series with the bulb
A
10 ohm
B
20 ohm
C
30 ohm
D
40 ohm
Answer
30 ohm
Explanation
Solution
By using Series resistanceR =(PRVoperating−VR)×VR
(As we discussed in theory) ⇒ R=90(120−30)×30=30Ω