Kakasa Ka Ba Sa b.e.e

KAKASA KA BA SA BASIC E.E? LET’s SE.E.

1. The substation bus bar is made up of 2 in. round copper bars 20 ft. long What is the resistance of each bar if resistivity is 1.724 X 10^-6 ohm-cm.A. 7.21X10^-5 ohmB. 13.8X10^-6 ohmC. 5.185X10^-5 ohmD. 2.96 X10 ^-5 ohm

2. Determine the resistance of a bus bar made of copper if the length is 10 meters long and the cross section is a 4X 4 sq. cm. Use the 1.7241 micro ohm-cm.

A. 2.121X10^-4ohmB. 4.312 X10^-4 ohmC. 3.431 X10^-5 ohmD. 1.078 X10 ^-4 ohm

3. Nichrome ribbon resistor elements each have a resistance of 1 ohm. The element is made from sheet of nichrome alloy, 0.025 cm. thick .If the width of the ribbon is 0.3 cm., what length is required per element? Assume specific resistance of nichrome to be 109 micro ohm-cmA. 68.8 cmB. 62.1 cmC. 70.7 cmD. 67.4 cm

4. A coil has 6000 turns of wire and a resistance of 380 ohms. The coil is rewound with the same quantity (weight) of wire, but has 13,400 turns. How many ohms will the new coil have?A. 1895 ohmsB. 1825 ohmsC. 1792 ohmsD. 1905 ohms

5. A conductor whose diameter is 0.175 in. has a resistance of 0.5 ohm. The wire is drawn through a series of dies until its diameter is reduced to 0.08 in. Assuming the specific resistance of the material remains constant what is the resistance of lengthened conductor?A. 11.45 ohmsB. 10.22 ohmsC. 12.75 ohmsD. 10.82 ohms

6. The resistance of a copper wire at 30 ℃ is 50 ohms. If the temperature coefficient of copper at 0℃ is 0.00427, what is the resistance at 100 ℃?

A. 72.26 ohmsB. 54.25 ohmsC. 63.24 ohmsD. 58.15 ohms7. The shunt field winding of shunt generator has a resistance of 80 ohms at 20 ℃. After several

hours of continuous operation, the winding temperature rises to 50 ℃. How much is the winding resistance under this condition. Assume the resistance temp. coef. Of copper to be 0.004 ohm per degree at 0℃.

BSME II-3 EDITION dHomZ^^


A. 88.89 ohmsB. 90.12 ohmsC. 85.22 ohmsD. 92.81ohms

8. The field windings of series motor have a resistance of 120 ohms at 15 ℃. After running for 2 hours the resistance increases to 140 ohm. If the temp. coef. Of the windings at 0 ℃ is 0.004, find the new temp. Of the windings.A. 60.4 ℃B. 59.2℃C. 58.4℃D. 53.7℃

9. The resistance of a wire is 126.48 ohms at 100 ℃ and 100 ohms at 30 ℃. Determine the temperature coef. Of copper 0 ℃.A. 0.00427B. 0.00615C. 0.0256D. 0.0356

10. Two wires A & B made from two different materials have temperature coef. Of resistance equal to 0.0025 ohm per ℃ respectively. It is desired to make a coil of wire having a resistance of 1200 ohms with a temperature coef. Of 0.001, using suitable lengths of the two given wires connected in series. Determine the required length of wire A?A. 5.5 mB. 6.2 mC. 6.0mD. 5.0 m

11. A cylindrical rubber insulated cable has a diameter of 0.18 in. and an insulation thickness of 0.25 in. If the specific resistance of rubber is 10 ^14 ohm-cm, determine the insulation resistance per 1000 ft length of the cable.A. 624MohmsB. 682 M ohmsC. 678 M ohmsD. 694 M ohms

12. The diameter of a given bare conductor is 0.50 in. A thermoplastic insulation with thickness of 0.1 in. is wrapped around to insulate the conductor. Determine the insulation resistance of this conductor per meter. Assume specific resistance of thermoplastic insulation to be 2 X10 ^14 ohm-cm.A. 107X 10^9 ohmsB. 105 X 10^9 ohmsC. 110 X 10^9 ohmsD. 109 X 10^9 ohms



13. A 120 V DC motor draws current of 100 A and is located 1000 ft from the supply source. If the diameter of the copper transmission line is 0.45 in., what must be the voltage of the supply?A. 125.32 VB. 130.24VC. 129. 32 VD. 127.05 V

14. The hot resistance of a n incandescent lamp is 10 ohms and the rated voltage is 50 V. Find the series resistance required to operate the lamp from an 80 V supply.A. 8 ohmsB. 4 ohmsC. 6 ohmsD. 10 ohms

15. Three resistors of 10, 15 and 20 ohms each are connected in parallel. What is the equivalent resistance?A. 45 ohmsB. 17.2 ohmsC. 0.22 ohmsD. 4.62 ohms

16. The equivalent resistance of three resistors A, B and C connected in parallel is 1.714 ohms. If A is twice of B and C is half as much as B, find the equivalent resistance when the three of them are connected are connected in series.A. 17.5 ohmsB. 21.0 ohmsC. 24.5 ohmsD. 28.0 ohms

17. Three resistors of 10, 12 and 15 ohms are connected in parallel. Evaluate the value of current to the parallel system that will make the current in the 10 ohm resistors equal to 2 A.A. 5 AB. 6AC. 4AD. None of these

18. 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 ohmsB. 9.25 ohmsC. 14.4 ohmsD. 21.2 ohms

19. 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 AC. 4.02 AD. 5.72 A

20. Two resistances of 10 and 15 ohms each respectively are connected in parallel. The two are ten connected in series with a 5- ohm resistance. It is then connected in a 12 V battery, what are the current and power?A. 1.2 A, 17.28 WB. 0.96 A, 11.52 WC. 1.09 A 13.1 WD. 1.5 A, 20.25 W

21. 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 parallel – connected resistors is equal to the power consumed by the 8- ohm resistor.A. 10 ohmsB. 16 ohmsC. 12 ohmsD. 20 ohms

22. A circuit consisting of three resistors rated: 10 ohms and 10 ohms are connected in delta. What would be the resistances of the equivalent wye connected load?A. 0.30, 0.23 and 0.15 ohmsB. 3.0, 4.0 and 5 ohmsC. 3.33, 4.44 and 6.66 ohmsD. 5.77, 8.66 and 11.55 ohms

23. The equivalent wye element of 3 equal resistors each equal to R and connected in delta isA. RB. 3R/2C. R/3D. 3R

24. A 12 V battery of 0.05 ohm resistance and another battery of 12 V and 0.075 ohm resistance supply power to a 2- ohm resistor. What is the current through the load?A. 5.85 AB. 5.63 AC. 5.72 AD. 5.91 A

25. Two equal resistances are connected in parallel across a 150 V DC source. What potential difference exists between the midpoint of one resistance and a point that is one-third from either end of the other resistance?A. 24 VB. 28 VC. 25 VD. 30 V



26. The lead storage batteries “A” and “B” are connected in parallel “A” has an open circuit voltage of 12 V and an internal resistance of 0.2 ohm. Battery “B” has an open circuit voltage of 12.2 V and an internal resistance of 0.3 ohm. If the two batteries together delivers power to a 0.5 ohm power resistor. Neglecting effects of temperature, how much current is contributed by battery “A”?A. 29.62 AB. 16.00 AC. 12.85 AD. 25.24 A

27. A charger, a battery and a load are connected in parallel. The voltage across the charger is 12.5 volts and the battery has an emf of 12 volts and the internal resistance of 0.1 ohm. The load consists of a 2 ohms resistor. Find the current through the charger.A. 6.61 AB. 6.25AC. 6.42 AD. 6.50 A

28. The insulation resistance of a kilometer of the cable having the diameter of 2 cm and an insulation thickness of 2 cm. is 600 ohms. If the thickness of the insulation is increased to 3 cm. find the insulation resistance of the cable.A. 725 ohmsB. 850 ohmsC. 757 ohmsD. 828 ohms

29. Ten cells each of emf 1.5 volts and internal resistance of 0.2 ohm are joined in parallel and connected to an external circuit resistance of 3 ohms. What is the current the load draws.A. 0.45 AB. 0.65 AC. 0.50 AD. 0.48 A

30. A variable resistor R is connected in parallel with a fixed resistor of 1.25 ohms. The combination is then connected across a 12 V battery with internal resistance 0.25 ohms. Solve for the maximum power that can be delivered to resistor R.A. 130.20WB. 115.52 WC. 120.21 WD. 142.42 W


Kakasa Ka Ba Sa b.e.e

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