Three identical bulbs, B1, B2 and B3 connected. Current of 3A is recorded by the ammeter when the bulbs glow.

Three identical bulbs, B1, B2 and B3 connected. A current of 3A is recorded by the ammeter when ​the bulbs glow. What happens when:

To the glow of the other two bulbs when one of them gets fused?

Assuming that B1 is fused, there supposedly will be no impact on the other two bulbs. The two bulbs will remain the same since they are dependent on the power. This happens because the potential difference and resistance of the other two bulbs remain the same, and do not get affected by an external fuse of another bulb.

To the reading of A1, A2, A3 and A when the bulb B2 gets fused? 

Considering that there are parallel connections, the net resistance should be:

1/R = 1/R+ 1/R+ 1/R3

Now, since the resistance remains same, thus, R’ = R/3

Hence, according to Ohm’s Law,

V = IR

Thus,

R = 4.5Ω

Assuming that B2 is fused, two bulbs, B1 and B3, remain parallel

Therefore, the net resistance in parallel combination is = 1/R’ = 2/R

⇒ R’ = 4.5/2 Ω

⇒ I = V/R’

⇒ I = 2 × 4.5 / 4.5

⇒ I = 2A

The distribution of current in both the bulbs will be1 A each.

How much power is dissipated in the circuit when all the three bulbs glow together?

The amount of power that is dissipated when all the three bulbs glow together:

P = V × I

Therefore, after replacing the values, we get,

P= 4.5 × 3

P = 13.5 W


Related Questions:

  1. How Do You Find The Resistance Of A Wire?
  2. Why is the curve representing Ohm's law linear?
  3. State Ohms law. How can it be verified experimentally?
  4. What Is The Formula Of Ammeter?
  5. What are the limitations of Ohm's Law?
  6. What is the necessary condition for a conductor to obey Ohm's Law?
  7. How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
  8. n identical light bulbs, each designed to draw P power from a certain voltage supply, are joined in series across that supply. The total power which they will draw is?
  9. Two bulbs are rated (P1, V) and (P2, V). If they are connected (i) in series and (ii) in parallel across a supply V Find the power dissipated in the two combinations in terms of P1 and P2.
  10. Does Current Increase With Voltage?
  11. The resistance R= V/I, where V=100 ± 5.0V and I = 10 ± 0.2A. What is the total error in R?
  12. State Ohms Law. Express It Mathematically. Define Si Unit Of Resistance.
  13. Is resistance constant in Ohm's law?
  14. Draw a circuit diagram to verify ohm’s law.
  15. How do you find the resistance in Ohm's law?
  16. What are the applications of ohm's law used in daily life?

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                        CBSE CLASS XII Previous Year Papers

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