Advertisements
Advertisements
Question
Calculate equivalent resistance in the following cases:
Advertisements
Solution
(i) Resistance P and Q are in series = 3 Ω + 3 Ω = 6 Ω
Resistance of 6 Ω segment and 3 Ω are parallel.
∴ `1/"R" = 1/6 + 1/3 = (1 + 2)/6 = 3/6` or R = 2Ω
(ii) Resistance of the arm PS = 2Ω +2Ω = 4Ω (in series)
Resistance of the arm QR = 2Ω + 2Ω = 4Ω (in series)
Resistance of the arm PQ, QR and RS are in series
= (4 + 4 + 4)Ω = 12Ω
Now resistance of the arm RS and arms (PQ + QR + RS) are in parallel.
`1/"R" = 1/4 + 1/12`
`= (3 + 1)/12 = 4/12`
or R = 3Ω
RELATED QUESTIONS
Complete the following :-
(b)
An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?
Show how would you join three resistors, each of resistance 9 Ω so that the equivalent resistance of the combination is
1) 13.5
2) 6 Ω
A resistor has a resistance of 176 ohms. How many of these resistors should be connected in parallel so that their combination draws a current of 5 amperes from a 220 volt supply line?
State how are the two resistors joined with a battery when equivalent resistance is less than either of the two resistances.
Calculate the equivalent resistance between the points A and B in Fig. if each resistance is 2·0 Ω.
A uniform wire with a resistance of 27 Ω is divided into three equal pieces and then they are joined in parallel. Find the equivalent resistance of the parallel combination.
Solve the following question:
In an electric circuit, two resistors of 12 0 each are joined in parallel to a 6 V battery. Find the current drawn from the battery.
State the S.I. unit of electrical resistance and define it.
A given wire is stretched to double its length. How will its resistance change?
