DC CIRCUITS POWERLINE

75問 • 2年前

問題一覧

What is the basic for declaring the direction of electric current is from positive terminal to negative terminal of a circuit?

Conventional

Which of the following will the effect of the electric shock in the human body depends on

Current flowing of the body

Which of the following conductors has the highest resistance?

Nichrome

In American wire gauge (AWG) as the number gage increase the wire diameter?

Decrease

* What is the value of the resistor with color coded Green-Blue-Red-Gold?

5,600 ohm +5%

A copper bar is 1/2 inch by 4 inches by 20 feet. If the resistivity of the copper bar is 10.37 ohms-cmf. What is the resistance of the copper bar?

8.15 × 10^-5 ohm

A cylindrical copper rod has a resistance R. It reformed to twice its original length with NoO change in volume. What is the resistance?

Nine identical wires, each of diameter d and learn L, and connected in series. The combination has the same resistance as single similar wire of length L but whose diamter is

d/3

A heating element consists of two wores of different materials connected in series. At 20°C, they have resistances of 600 ohms and 300 ohms, and average temperature coefficients of 0.001 1/°C and 0.004 1/°C respectively. What id the heating element total resistance at 50°C?

954 ohms

A 100-volt carbon filament lamp takes 1 Amp when glowing with a filament temperature of 1615°C. Calculate the momentary current when lamp is first switched on in air temperature of 15°C. The temperature coefficient of redistance for carbon may be taken as -0.000265 per °C at 50°C

0.58 Amp

A dc motor 120 volts has 100 Amp rated current. the allowable voltage drop 3% of input voltage. Find the maximum distance from the supply if the wire has a diameter of 316 mils and resistivity of wire is 10.4 ohm-cmf

178 ft

Suppose that the fundamental dimension are taken to be force (F), velocity (V) and time (T). What are the dimension of potential energy?

FVT

Resistor 1 has twice the resistance of resistor 2. They are connected in parallel to a battery.Find the ratio of terminal energy generation rate in resistor 1 to that of resistor 2.

1:2

* A 15 ohm resistir is connected in parallel with a series combination of resistor of 8 ohms and 12 ohms. If the voltage drop across the 8 ohm resistor is 48 volts, what is the current in Amp?

A 20 phm resistor is connected in parallel with a variable resistor R. The Parallel combinationis then connected in series with a 4 ohm resistor and connected acriss a 240 V source. Determine the minimum value of R if the power of R is equal to the power taken by the 4 ohm resistor

7.64 ohms

Find the work in kWh to lift 1 ton at a height of 55 ft for 10 sec. The motor geat efficiency is 51%.

0.083

A process equipment contains 100 gallons of water at 25°C. It id required to bring it to boiling point in 10minutes. The heat loss is edtimated to be 5%. What is the kW rating of the heater?

207

A Car battery is rated at 80 amp-hr. An ampere-hour is a unit of

Charge

A 12 volt battery 50 Amp-hr capacity. The internal resistance is 0.1 ohm. A 5 ohm resistor is connected for 5 hours. How many Amp-hours are still left?

38.23

What is the power absorbeb by 900 phm resistor in the network show below

1.44 Watts

Twelve resistance 1 ohm each are arranged along the edge of a cube with junctions at corners. What resistance will be measured between terminals of symmetrically opposite corners of the cube?

5/6 ohm

Superposition theorem can be applied only to circuits having

Linear bilateral elements

In any linear bilateral network if a source of emf E in any branch produces a current I in any other branch then some emf acting in second branch would produce the same current I in the first branch. The above statement is associated with.

Reciprocity theorem

If an electrical network having one or more voltage source, is trnasformed into equivalent electrical network with single voltage source (which is short circuit current of previous circuit? with parallel internal resistance of the network with all current source replaced by thier internal resistance. The above illustration is called

Norton's Theorem

Two 24 volt's battery supply power to a 10 phm load. One battery has 0.2 phm internal resistance while the other has 0.4 ohm. What is the load voltage and power doeas this load draws?

23.68 Volts & 56.1 Watts

From the given network shown in Fig.2 determine the respective current supplied by the 10 Volt, 12 Volt and 24 Volt batteries.

1.5 Amp, 1.9 Amp, -2.2 Amp

Find the current flowing in the 4 ohm resistor in the network shown using Thevenin's theorem Fig 3.

1.667 Amp

A barangay power station supplies 60 kW to a load over 2,500 ft 100 sq mm, 2 conductir copperfeeder the redistance of which is 0.078 phm per 1000 ft. The busbar voltage is maintained at 600 V. Determine the maximum power which dan be transmitted.

230.77 kW

The norton equivalent of a circuit consists of 2 Amp current source in parallel with a 4 ohm resistor Thevenin's equivalent of this circuit is a ________ Volt source in series with a _______ ohm resistor.

8, 4

In flemming's Right Hand Rule, which finger point the direction of current?

Middle

The magnetic torque ecerted on a flat current carrying loop of wire by a uniform magnetic field " B " is

maximum when the plane of the loop is parallel to " B "

The unit of magnetic dipole moment are

ampere-meter^2

A substance or material having relative permeability of less than unity is classfied as

Para-magnetic

Permeability in a magnetic circuit corresponds to ________ in an electric circuit.

conductivity

The direction of indeced e.m.f can be found by

Lenz's law

In electromagnetic induction three of the following terms are identical. Name the ONE that is NOT

Flux

Which of the following statements is TRUE for steady state conditions in a circuit powered by a dry cell?

Induction behave as short circuit

An emf induced by the changing of current in the neighboring coil is called

mutually induced

Find the average flux passing thriugh a 0.5 m long inductor csrrying 10 Amp current if it has 100 turns and cross sectional area of 0.1 sq. meter

251x10^-6 Wb

A 2-T uniform magnetic field makes an angle of 30° with the z axis. The magnetic flux thriugh a 3m^2 portiin of the x-yp plane is _______Wb

5.2

Determine the force in pounds upon each side of a coil of 40 turns carrying a current of 15 Amp if the axial legth of the coil is 10 inches and the flux density is 20,000 lines per sq. inch. The conductirs are at right angle to the flux

10.6 lbs

You are facing loop a wire which carries a clockwise current of 3.0 Amp and which surrounds an area of 5.8 x 10^-2 m^2. The magnetic dipoke moment of the loop is ______

0.17 A-m^2; away from you

A regular coil of 25 loops is suspended in a field of magnetic induction of 0.2 tesla. Tje plane of the coil is parallel to the direction of the field. The dimension of the coil are 15 cm perpendicular to the field and 12 cm parallel to them. What is the current in the coils if there is a torque of 5.4 Newton-meter acting on it?

60 amp

A magnetic circuit consists of silicon steel of 3000 permeability and an air gap. The length of the steel core is 10 cm and the air gap is 2 cm both have the same cross-section of 1.5 sq.cm. A current of 1/2 Amp flows through the windings to produce 2351 Maxwell flux. How many turns are there in the coil?

500 turns

Pole strength 160 and 192 are seperated by a distance has a force of 19600 dynes. What is the distance in cm? interger choices.

Two parallel wires carrying equal current of 10 A attract each other with a force of 1 mN. if both current are doubled the force of attraction will be.

4 mN

A current of 2 Amp through coil sets up flux linkages of 4 Wb-turns. What is the inductance of the coil?

2 H

A 3-H inductor has 2000 turns. How many turns must be added to increase the inductance to 5-H?

582

A magnetic coil produces 100,000 maxwells with 1,000 turns and with a current of 2 Amp. The current is cut off and the flux collapses in 0.01 sec. What is the average voltage taht will appear across the coil?

100 V

A 50 mH induction cames a current of 10 Amp which reverses in 5 milliseconds. What is the average voltage induced in the inductor because of this current reversal?

100 volts

A metal transport plane has a wing spread of 88 ft. Whqt is the difference of potential exists between the extermities of the wigns. When the plane moves horizontally. with the speed of 150 miles per hour?. The value of the verticak component of the earth's magnetic field is 0.65 Gauss at the plane

0.12 Volt

Find the value of an inductor which carries 2 Amp of steady current and in which 20 Joules of energy is stored?

10 H

* Two identical coupled coils have an equivalent inductance of 80 mH when connected in series aiding and 35 mH in series opposing. What is the value of coefficient of coupling k?

0.391

Two coils of inductance 6 & 4 Henries are connected in parallel such that its coefficient of coupling is 41% with mutual inductance opposes the self inductance. What is the total inductance of the combination?

1.43 H

When one coil of magnetically coupled pair has a current of 5 Amp, the resulting flux 11 = 0.4 mWb and flux 12 = 0.8 mWb respectively. if the turns are N1 = 500 and N2 = 1500. Find L1 and coupling coefficient k.

120 mH, 0.67

The coulomb force F acts on two charges a distance, r apart. What is F proportional to?

1/r^2

Which statement about a charge placed on a dielectric material is TRUE?

The charge is confined to the region in which the charge was placed

What will happen to an insulating medium with voltage more than breakdown voltage is applied?

it will get punctured

Permitivity is expressed in ______

Farad/meter

The inverse capacitance is called ______

Elastance

For which of the following parameter variation, the capacitance of the capacitor remains unaffected?

Thickness of the plates

Equal amount of electrons are placed in two spheres 3 cm apart in air. If the resultant force is 4 kN. How many electrons does each spheres contain?

1.25 x 10^14

Four 3 pCoul spheres are in corners of a square 1 cm on sides. Find the force in Newton?

15.5 x 10^-10

Two equal charges of opposite signs are sperated by a horizontal distance of 70 mm. If the resultant electric field at the midpoint of the line is 4x10^4 N/C. Find the magnitudeof each charge

2.7 nC

A confenser of 8 micro farad capacitance is charge by connecting its plate to a 220 volt battery. What is the charge in micro coulomb?

1760

A plate capacitor isnmade up of 501 sheets of aluminum 25 cm x 30 cm with a dielectric of paraffin paper 0.0015 cm thick. What is the capacitance in micro farads of the condenser ( K for paraffin paper is 2.3)

Given a charge of 36 nCoul at time of 4 millisecond. Find the current.

9 x 10^-6 A

Find the value of a capacitor with 500 Volts across it in which 20 Joule of energy is stored

160 micro-farad

Three capacitor are connected in series 6,7 and 18 micro farad across a 100 Volt source. What is the voltage across the 7 micro-farad capacitor?

39.1 Volts

A capacitor "C" is connected in parallel woth a series combination of capacitor of 8 uF and 4 uF. The voltage drop across capacitor "C" is 12 Volts. The 3 capacitor have been connected for sometimes and have reached their predent value. Find the voltage across the 8 uF capacitor.

4 Volts

Which of the following can be used to measure small dc generated voltages?

Galvanometer

For measuring the resistance of the elements of an attenuator which of the following is the best choice?

Wheatstone bridge

* A certain galvanometer has a resistance of 100 ohm and requieres 1 mA for full scale deflection. To make this into a voltmeter reading of 1 full scale. Connect a resistance of?

900 ohm in series

A certain voltmeter has an internal resistance if 10 k-ohm and a range 0 - 12 V. To extend its range to 120 V user a series resistance if________ ohm

90,000

To roughly check his kWh meter an electrician hook up a wattmeter. he switched in the load he counted 5 rev in 18 sec, the meter constant is 3.2. The wattmeter reads 368 Watts. What is the error of the meter?

5% slower

AC CIRCUIT POWERLINE

premopremo remo · 100問 · 2年前

AC CIRCUIT POWERLINE