DC ELECTRIC CIRCUITS - Day 2

Question 1: EE Board October 1997

     A 5-ohm resistance is connected in parallel with a 10-ohm resistance. Another set, a 6-ohm and an 8-ohm resistances are also connected in parallel. The two sets are connected in series. What is the equivalent resistance?

A. 6.76 ohms

B. 9.25 ohms

C. 14.4 ohms

D. 21.2 ohms

Question 2: EE Board March 1998

     Two resistances of 10 and 15 ohms each respectively are connected in parallel. The two are then connected in series with a 5-ohm resistance. What is the equivalent resistance?

A. 11 ohms

B. 12 ohms

C. 10 ohms

D. 9 ohms

Question 3:

     From the circuit as shown, determine the resistance between terminals a &

                                              ___________

                            a     1 Ω      | 2 Ω      3 Ω |     4 Ω        b

–—^^^—–^^^—–^^^—–^^^——–

                                                         |_____________|

A. 1.000 Ω

B. 1.923 Ω

C. 2.083 Ω

D. 2.352 Ω

Question 4: EE Board October 1997

     A 10-ohm and a 20-ohm resistance are connected in parallel. Another resistance of 5-ohm is connected in series with the two. If the supply voltage is 48 volts, what is the current through the 10-ohm resistance?

A. 3.21 A

B. 2.74 A

C. 4.02 A

D. 5.72 A

Question 5:

     A 30-ohm resistor is connected in parallel with a variable resistance R. The parallel combination is then connected in series with a 6-ohm resistor and connected across a 120 V source. Find the minimum value of R if the power taken by R is equal to the power taken by the 6-ohm resistor.

A. 10.35 Ω

B. 12.24 Ω

C. 10.24 Ω

D. 11.46 Ω

Question 6: EE Board March 1998

     Two resistances of 10 and 15 ohms, each respectively are connected in parallel. The two are then connected in series with a 5-ohm resistance. It is then connected across a 12-V battery, what are the current and power?

A. 1.2 A, 17.28 W

B. 0.96 A, 11.52 W

C. 1.09 A, 13.1 W

D. 1.5 A, 20.25 W

Question 7:

     An 8-ohm resistor is connected in series with a parallel combination of two resistors, R and 24 ohms. Determine R if the power consumed by the parllel-connected resistors is equal to the power consumed by the 8-ohm resistor.

A. 10 ohms

B. 16 ohms

C. 12 ohms

D. 20 ohms

Question 8:

     A multi-tap resistor R is connected across a 220-V supply. A voltmeter whose internal resistance is 15-k Ω is connected across the center tap and one end of the supply terminals. If the voltmeter registers 100 V, what is the value of resistor R.

A. 5.5 k Ω

B. 5.0 k Ω

C. 6.0 k Ω

D. 6.5 k Ω

Question 9:

     A potential divider of resistance of 50 ohms is connected across a 100 V DC source. A load resistance of 10 ohms is connected across a tap in the potential divider and the negative terminal of the source. If a current of 4 A flows towards the load, what is the current supplied by the source?

A. 5.32 A

B. 5.05 A

C. 5.21 A

D. 5.48 A

Question 10:

Two resistors A and B are connected in series across a 220 V DC source. When a voltmeter with an internal resistance of 10 k Ω ohms, is connected across resistor A, the instrument reads 100 V and when connected across resistor B, it reads 80 volts. Find the resistance of resistor A.

A. 4 k Ω

B. 3 k Ω

C. 5 k Ω

D. 6 k Ω