How does current affect brightness

Voltage drop IR is the same across parallel branches. If R is the same, I must also be the same. If R is different, I must also be different by the same factor. They are inversely related. In this problem, you are asked to understand current flow in a circuit conceptually.

You know that the current out through the battery splits and recombines at junctions and electrons are not used up. Furthermore, you know that current does not split evenly at a junction. Rather, more current passes through branches that have less resistance and IR always has the same value for branches in the same parallel elemenet.

This understanding is all that is required in order to determine what fraction of the current from the battery goes through each branch of a circuit.

Note that you can also use these conceptual ideas to solve circuits mathematically. If you break down the circuit into its equivalent resistance go to the Draw page of Circuit II and use that to find the total current the green current in this case , you can find the other currents based on their fraction of the green current.

This is exactly the same circuit as in Circuit II. Click here to go to Circuit II and work it mathematically. To really understand the process well, take a look at both the conceptual and mathematical solutions and see that they are the same. Rank the brightness of the identical light bulbs in the circuit below.

Don't I need numbers to work this problem? View Queries. How did you know all three of the "yellow" branches have the same current? Doesn't the current divide and then divide again? Remember, energy is converted in resistors but electrons are not used up.

FAQs The light bulbs are identical. Doesn't that mean they all have the same brightness? How would I work this problem mathematically? The light bulbs are identical. Repeat this method for each of the following circuits:.

Circuit 3. Ammeter on each branch, voltmeter across each bulb. Circuit 4. Circuit 5. Ammeter next to each bulb, voltmeter across each bulb. Circuit 6. A suitable results table for each circuit might be:. These are example results for Circuit 5 parallel circuit, two bulbs on one branch, single bulb on the other branch. When in series, bulbs become dimmer as the potential difference is shared equally across the bulbs. SBI Clerk. SBI PO.

IBPS Clerk. Forgot Password? Brightness of bulb depends on voltage or current? The brightness depends on power. Example Illustration: If you connect a long bulb and a round bulb in series, the long bulb glows but the round bulb does not. Hence, the brightness of a bulb depends on power i.

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