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How many coulombs are provided by a current of 0.010 mA in the calculator battery that can operate for 1000 hours?

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Important Questions on Current Electricity

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The current density in a cylindrical wire of radius r=4.0 mm is 1.0×106 A2 m2. The current through the outer portion of the wire between radial distances r2 and r is xπ A; where x is
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Define current density. Write an expression which connects current density with drift speed.

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The current density in a cylindrical wire of radius 4 mm is 4×106 A m-2. The current through the outer portion of the wire between radial distances R2 and R is _____ π A.
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Which of the following acts as a circuit protective device?
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The current in a conductor varies with time t as I=2t+3t2, where I is in ampere and t in seconds. Electric charge flowing through a section of the conductor during t=2 sec to t=3 sec is
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Across a metallic conductor of non-uniform cross section a constant potential difference is applied. The quantity which remains constant along the conductor is:
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Write down the formula for the relation of current density, specific conductivity and the electric field.
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A conducting wire of length l, area of cross-section A and electric resistivity ρ is connected between the terminals of a battery. A potential difference V is developed between its ends, causing an electric current. If the length of the wire of the same material is doubled and the area of cross-section is halved, the resultant current would be___

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A current through a wire depends on time as i=α0t+βt2, where α0=20 A s-1 and β=8 A s-2. Find the charge crossed through a section of the wire in 15 s.
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A current of 5 A is passing through a non-linear magnesium wire of cross-section 0.04 m2. At every point the direction of current density is at an angle of 60° with the unit vector of area of cross-section.
The magnitude of electric field at every point of the conductor is: (resistivity of magnesium ρ=44×10-8 Ωm)
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Electric field and current density have relation
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A circular wire has current density J=2×1010Am2r2 where r is the radial distance, out of the wire radius is 2 mm. The end-to-end potential applied to the wire is 50 V. How much energy (in joule) is converted to thermal energy in 100 s?
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The potential difference between points A and B of adjoining figure is

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MEDIUM

Current density in a cylindrical wire of radius R varies with radial distance as βr+r02. The current through the section of the wire shown in the figure is.

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Estimate the magnitude of current that passes through a wire, if 0.1 mol of electrons flow through it in 40 min. (Assume Avogadro number =6×1023)
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The charge flowing in a conductor changes with time as Qt=αt-βt2+γt3, where α, β and γ are constants. Minimum value of current is:
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The current flowing in a copper voltmeter is 1.6 A. The number of Cu++ ions deposited at the cathode per minute is
HARD
A steady current I is set up in a wire whose cross-sectional area decreases in the direction of the flow of the current. Then, as we examine the narrowing region,


 
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A conductor carries a current of 300 mA. The number of electrons passing through it in 1 minute are ___ .
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Eight amperes of current is passed through a wire for 10 minutes . Calculate charge passed through the wire -