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प्रश्न
(a) drift speed
(b) current density
(c) electric current
(d) electric field
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उत्तर
The electric current will remain constant in a wire whose cross-sectional area is increasing linearly from its one end to the other, is connected across a battery of V volts.
Because current is the only quantity that does not depend on the area of cross- sections of the wire.
`I=(dq)/(dt)`, that is the rate of flow of charge, where as drift speed, current density and electric field are depends on the increasing area of cross-section with the following relations:
Drift speed: `ν_d=I/(An""e)`
Current density = `I/A`
Electric field = `J/σ`
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संबंधित प्रश्न
Define the term drift velocity.
Derive an expression for drift velocity of free electrons.
Write its (‘mobility’ of charge carriers) S.I. unit
The number density of free electrons in a copper conductor is 8.5 × 1028 m−3. How long does an electron take to drift from one end of a wire 3.0 m long to its other end? The area of cross-section of the wire is 2.0 × 10−6 m2 and it is carrying a current of 3.0 A.
Why alloys like constantan and manganin are used for making standard resistors?
Consider the following statements.
(A) Free-electron density is different in different metals.
(B) Free-electron density in a metal depends on temperature.
Peltier Effect is caused _______________ .
Metals are good conductor of heat than insulator because
Is the momentum conserved when charge crosses a junction in an electric circuit? Why or why not?
- Consider circuit in figure. How much energy is absorbed by electrons from the initial state of no current (ignore thermal motion) to the state of drift velocity?
- Electrons give up energy at the rate of RI2 per second to the thermal energy. What time scale would one associate with energy in problem (a)? n = no of electron/volume = 1029/m3, length of circuit = 10 cm, cross-section = A = (1mm)2
Define relaxation time.
