## Electric Current Questions and Answers

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A neutral conductor contains a hollow cavity, in which there is a +100nC point charge. A charged rod then transfers -50nC to the conductor. Afterward, what is the charge: a. on the inner wall of the c

In a certain stereo system, each speaker has a resistance of 4.00 \Omega. The system is rated at 60.0 W in each channel, and each speaker circuit includes a fuse rated 4.00 A. Is this system adequatel

A synchrotron radiation facility consists of a circular ring that has a 48.0 m radius and creates an electron beam with a current of 497 mA when the electrons have a speed approximately equal to the s

If 3.25*10^{-3} kg of gold is deposited onto the negative electrode of an electrolytic cell in a period of 2.78 hours, what is the current through this cell in amperes? Assume that the gold ions carr

How many electrons give a charge of -3.30 nc?

If a current of 80.0 mA exists in a metal wire, how many electrons flow past a given cross-section of the wire in 10.0 min?

An insulated piston?cylinder device initially contains 0.3 m3 of carbon dioxide at 200 kPa and 27 C. An electric switch is turned on, and a 110-V source supplies current to a resistance heater inside the cylinder for a period of 10 min. The pressure is h

The lighting needs of a storage room are being met by six fluorescent light fixtures, each fixture containing four lamps rated at 60 W each. All the lamps are on during operating hours of the facility, which are 6 a.m. to 6 p.m. 365 days a year. The stora

What is virtual current?

A copper wire of radius 0.1 mm and resistance 1 k\Omega is connected across a power supply of 20 V. a) How many electrons are transferred per second between the supply and the wire at one end? b) Wh

An inductor has a peak current of 330 mu A when the peak voltage at 44 MHz is 3.6 V. 1) What is the inductance? 2) If the voltage is held constant, what is the peak current at 88 MHz ?

One end of an aluminum wire of 0.125 cm in diameter is welded to a copper wire of 0.25 cm in diameter. The composite wire carries a current of 8 mA. What is the current density in each wire?

The drift speed of the electrons in a wire depends strongly on which of the following factors? a. the cross-sectional are of the wire b. the mass of the wire c. the temperature of the wire d. the

If you rub a piece of PVC pipe with some wool and touch the PVC to Aluminum foil. Will the PVC be charged after rubbing it with wool? Will the aluminum be charged? Finally can the PVC cause the alumin

Why does rubbing the cell increase the brightness of the bulb?

In an electrolyte, the positive ions move from left to right and negative ions move from right to left. Is there a net current? If yes, in what direction?

Consider a wire of length 4 m and cross-sectional area 1 mm^2 carrying a current 2 A. If each cubic meter of the material contains 10^{29} free electrons, find the average time taken by an electron to

An X-ray tube operates at 95 kV with a current of 25 mA and nearly all the electron energy goes into heat. If the specific heat of the 0.085-kg plate is 0.11 kcal/kg.degC, what will be the temperature

An electroplating cell operates for 35 minutes with a current of 1.9 A. Calculate the amount, in moles, of electrons transferred.

Given that a battery produces a current of 2.5 A that passes through molten zinc chloride for 3 minutes, what charge would be dissipated through the electrolyte?

A cell, transferred 0.146 mol of electrons with a constant current of 1.24 A. How long, in hours, did this take?

If a current is the result of the flow of electrons, then why doesn't wire get thin at one end and thicker at the other?

Why does current flow in the opposite direction of electrons in a conducting wire?

A 20.0-cm-long hollow nichrome tube of inner diameter 1.70 mm, outer diameter 4.40 mm is connected to a 2.00 V battery. What is the current in the tube?

In a synchrotron, electrons are accelerated to speeds close to the speed of light v?c?3 108 m/s Suppose that in a synchrotron, 100 billion (1011) electrons move in a circular orbit of circumference L=

In a lightning strike, a charge of 18 coulombs is transferred between a cloud and the ground in 2.0 \times 10^{-2} second at a potential difference of 1.5 \times 10^6 volts. What is the average curren

How long, in minutes, does it take a current of 1.60 A to transfer a charge of 375 C?

An aluminum wire has a resistance of 1.8 \times 10^{-3} \Omega/m and carries a 200 \ A current. What is the power dissipated by 10 \ km of such wire?

PartB Every minute, 120 C of charge flow through this cross section of the wire. The wire's curre... PartB Every minute, 120 C of charge flow through this cross section of the wire. The wire's current

Why do current flows in the opposite direction of electrons movement?

The belt of a Van de Graaff generator carries a surface charge density of 4.50 mC/m^2. The belt is 0.500 m wide and moves at 22.0 m/s. a) What current does the belt carry? b) If the potential of the

The charge flowing through a light bulb attached to a 12.0-V battery in 14.0 s is 30.0 degrees C. On the average, how many electrons pass a point in the filament of the bulb per second?

An inductor with an inductance of 2.30 H and a resistor with a resistance of 15.0 \Omega are connected to the terminals of a battery with an e.m.f of 7.50 V and negligible internal resistance. (a) Fi

In an old house, the wires leading to a 120 V outlet have a total resistance of 0.45 \Omega. When you plug in a hairdryer, it draws a 15 A current. a) How much does the outlet voltage decrease due to

An electric heater draws a steady 15.0 A on a 120.0 V line. How much power does it require and how much does it cost per month (30 days) if it operates 3.0 h per day and the electric company charges 1

Which of the following statement is true about current flow. a) Current flows along lines of equal potential. b) Current flows from low potential to high potential. c) Current flows from high poten

If a current is composed of Na+ ions (q = +e), how many such ions flow in 0.7 s?

A circular armature coil is used in a motor with a uniform magnetic field of 3.80 T. The coil has a diameter 80 cm, a resistance of 25 ohms, and generates a back emf of 103 VRMS when running a full sp

A circular armature coil is used in a motor with a uniform magnetic field of 4.30 T. The coil has a diameter of 85 cm, a resistance of 50 ohms, and generates a back emf of 108 V_{RMS} when running at

There are two identical, positively charged conducting spheres fixed in space. The spheres are 32.4 cm apart (center to center) and repel each other with an electrostatic force of F 1 = 0.0750 N. The

An inductor (L = 100mH), a resistor (R = 100\Omega) and a battery (E = 100V) are initially connected in series. After a long time the battery is disconnected after short circuiting the points A and B.

A long straight wire is fixed horizontally and carries a current of 50 A. A second wire having a linear mass density of 1 \times 10^{-4} kg/mm is placed parallel and above the first wire at a separati

Typical household currents are on the order of a few amperes. If a 1.63 A current flows through the leads of an electrical appliance, how many electrons per second pass through it? If a 1.63 A current

Electron guns are used in x-ray machines. The electrons are accelerated through a relatively large voltage and directed onto a metal target, producing x-rays. How many electrons per second strike the

A hair drier uses 12 A at 116 V. It is used with a transformer in England, where the line voltage is 235 V. What should be the ratio of the turns of the transformer (primary to secondary)? What curren

The current in a 100-watt lightbulb is 0.900 A. The filament inside the bulb is 0.120 mm in diameter. What is the current density in filament? What is the electron current in the filament?

A current I=1A flows along a thin-walled cylinder of radius R=4cm. What pressure in Pascals do the walls of the cylinder experience? Assume that the current is uniformly distributed. Bonus thing to th

Copper wire with a diameter of 1.5mm is joined to an aluminum wire, which has a diameter of 2.3mm. The wire carries a current of 1.2A. What is the current density in each wire?

A car battery has a rating of 200 ampere hours (Ah). This rating is one indication of the total charge that the battery can provide to a circuit, before failing. What is the total charge (in coulombs)

A steady current of 2A flows in a coil of emf 12V for 0.4s. A back emf of 3V was induced during this period. The stored energy in the loop that can be utilized is?

A car battery is rated at 90 A hr, meaning that it can supply a 90 A current for 1 hr before being completely discharged. If you leave your headlights on until the battery is completely dead, how much

If a metal wire carries a current of 79.0 mA, how long does it take for 7.90 \times 10^{20} electrons to pass a given cross-sectional area anywhere along the wire? The fundamental charge is 1.602

Assuming 95.0% efficiency for the conversion of electrical power by the motor, what current must the 12.0-V batteries of a 768-kg electric car be able to supply to do the following? (a) accelerate fro

Describe any five safety measures that should be taken while dealing with electric appliance connected in domestic electric circuit.

Does a wire carry the current charge?

What is meant by flow of electrons?

The current in a 100 watt lightbulb is 0.900 A. The filament inside the bulb is 0.300 mm in diameter. What is the electron current in the filament?

When electric current is flowing in a metal, the electrons are moving Answer at the speed ... When electric current is flowing in a metal, the electrons are moving Answer at the speed of light. at the

A heart defibrillator applies a voltage of 9000 V across a patient's torso for 5.00 ms in an attempt to restore normal beating. If a total energy of 500 J is dissipated during the application of the d

A large lightning bolt had a 20,000-A current and moved 30.0 degrees C of charge. What was its duration?(Answer in ms.)