Q&A - Ask Doubts and Get Answers
Q

I have a doubt, kindly clarify. Four identical electrical lamps are labelled 1.5V, 0.5A which describes the condition necessary for them to operate at normal brightness. A 12V battery of negligible internal resistance is connected to lamps as shown,

Four identical electrical lamps are labelled 1.5V, 0.5A which describes the condition necessary for them to operate at normal brightness. A 12V battery of negligible internal resistance is connected to lamps as shown, then

  • Option 1)

    The value of R for normal brightness of each lamp is  \frac{3}{4} \Omega

  • Option 2)

    The value of R for normal brightness of each lamp is \frac{21}{4} \Omega

  • Option 3)

    Total power dissipated in circuit when all lamps are normally bright is 24W

  • Option 4)

    Power dissipated in R is 21W when all lamps are normally bright

 
Answers (1)
179 Views

V = IR   \Rightarrow R=3 \Omega

For normal brightness current through each bulb is 0.5 A

Therefore, Total current = 2A

I=\frac{21}{4} \Omega


Option 1)

The value of R for normal brightness of each lamp is  \frac{3}{4} \Omega

Incorrect

Option 2)

The value of R for normal brightness of each lamp is \frac{21}{4} \Omega

Correct

Option 3)

Total power dissipated in circuit when all lamps are normally bright is 24W

Incorrect

Option 4)

Power dissipated in R is 21W when all lamps are normally bright

Incorrect

Exams
Articles
Questions