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JAYPEE INSTITUTE OF INFORMATION TECHNOLOGY
Electronics and Communication Engineering
Electrical Circuit Analysis (10B11EC111) – 2011 ODD SEM
TUTORIAL 1: REVISION
1. Using minimum number of 1K resistors only, synthesize a resistor of value 3/5 K and 5/3 K.
2. Find the effective resistance between terminals A and B for the networks given in Fig. 1.1.
[Ans. (a) 12 Ω; (b) 5 Ω; (c) 10R/3 (d) 3 Ω (e) 4 Ω]
Fig. 1.1
3.
The resistance of two coils is 25 ohms when connected in series, and 6 ohms when connected in
parallel. Determine the individual resistances of the two coils.
[Ans. 15 Ω, 10 Ω]
4.
Determine the current Ix flowing through the 3-Ω resistor in the circuit of Fig. 1.2.
Fig. 1.2
[Ans. 4/3 A]
Fig. 1.3
5.
A resistance of 8 ohms is connected in series with a parallel combination of 12 ohms and 24
ohms. The whole circuit is connected across a 100-V supply. Find (a) the current drawn from the
supply, (b) the voltage across 8-ohm resistance, and (c) the currents flowing in 12-ohm and 24ohm resistances.
[Ans. (a) 6.25 A; (b) 50 V; (c) 4.17, 2.08 A]
6.
Determine I, I1, I2, Vab, and Vbc in the network of Fig. 1.3.
[Ans. 3 A, 1 A, 2A, 6 V, 12 V]
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7.
Calculate the current drawn from a 12-V supply with internal resistance 0.5 Ω by the infinite
ladder network, each resistance being 1 ohm, in Fig. 1.4.
[Ans. 3.71 A]
Fig. 1.4
8.
For the circuit shown in Fig. 1.5, find (a) the equivalent resistance between points A and B, (b)
the current and power supplied by the battery.
[Ans. (a) 8 Ω; (b) 6 A, 288 W]
9.
Determine the value of resistance R¸ if the power dissipated in 10-ohm resistance is 360 W in the
circuit of Fig. 1.6.
[Ans. 36 Ω]
Fig. 1.5
Fig. 1.6
10. When two resistances R1 and R2 are connected in parallel, they dissipate four times the power that
they dissipate when they are connected in series with the same ideal source of emf. If R1 = 3 Ω,
find R2.
[Ans. 3 Ω]
11. If two electric bulbs, each designed to operate with a power of 500 W in 220-V line, are put in
series in a 110-V line, what will be the power dissipated by each bulb?
[Ans. 31.25 W]
12. The current in the 6-ohm resistor of the network shown in Fig. 1.7 is 2 A. Find the currents in all
other resistors and the voltage across the network.
[Ans. 3.5 A, 1.5 A, 2.5 A, 1 A, 46 V]
Fig. 1.7
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13. In the network shown in Fig. 1.8, calculate (a) the current in the other resistances, (b) the value of
the unknown resistance X, and (c) the equivalent resistance between points A and B.
[Ans. (a) 2 A, 1 A, 2 A; (b) 15 Ω; (c) 3 Ω]
Fig. 1.8
Fig. 1.9
14. Find the voltage V for the circuit shown in Fig. 1.9.
[Ans. 310 V]
15. In the circuit shown in Fig. 1.10, find (a) the current in 15-Ω resistance, (b) the voltage across 18Ω resistance, and (c) the power dissipated in 7-Ω resistance.
[Ans. (a) 6.33 A; (b) 18 V; (c) 77.6 W]
16. If the total power dissipated in the network shown in Fig. 1.11 is 16 W, calculate the value of R
and the total current.
[Ans. 6 Ω; 2 A]
Fig. 1.10
Fig. 1.11
17. The equivalent resistance of four resistances joined in parallel is 20 ohms. The current flowing
through them are 0.6 A, 0.3 A, 0.2 A and 0.1 A, respectively. Find the value of each resistance.
[Ans. 40 Ω, 80 Ω, 120 Ω, 240 Ω]
18. A resistance of 10 ohms is connected in series with a combination of two resistances arranged in
parallel, each of 20 ohms. Calculate the value of resistance which should be shunted across the
parallel combination so that the total current drawn by the circuit is 1.5 A with applied voltage of
20 V.
[Ans. 5 ohms]
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