00:01
Hi, in the question we are given three circuits with identical batteries with voltage b and identical bulbs with resistances are on each of the bulb.
00:15
We are asked to rank the bulb according to the brightness.
00:20
So let us calculate the current flowing through each bulb because the brightness is depending on the current flowing through the bulb.
00:28
So circuit 1 we will get the current i is equal to v by r.
00:35
In second circuit we will get current i is equal to voltage by r equivalent we have two resistors connected in series so r equivalent is equal to 2r so the current through each bulb is equal to v by 2r.
00:56
In the third circuit we will get the current i is equal to again it is v by r equivalent.
01:03
The two resistors are connected in parallel therefore r equivalent is equal to r by 2 and we will get the current i is equal to v r by 2.
01:13
So it is 2v by r.
01:15
We can write the current through each bulb i a is equal to v by r i b is equal to i c.
01:27
Is equal to v by 2 r and i d is equal to i e is equal to 2 v by r by 2 that is v by r.
01:43
We are dividing this by 2 because the current is equally divided among these two branches because they are having same resistances.
01:54
Now let us compare the brightness.
01:56
Since a, d and e have same current flowing through it, the brightness of a, d and e will be same and in b and c we have less current flowing through it.
02:10
Therefore it will be less brighter than a, d and e.
02:15
Hence we can rank the bulbs as a is equal to d is equal to e then b is equal to c.
02:25
So based on brightness of the bulb bulbs a is equal equal to d is equal to e which is brighter than b equal to c.
02:33
Now coming to the second part of the question.
02:37
In the second part we are given a circuit with bulbs a, b, c and d and we are asked to analyze the bulbs and rank the bulb according to their brightness.
02:52
So let i be the current flowing through the circuit.
02:55
Then i current will flow through a.
02:57
It will get split into b and c if you will be the current...