Q. 755.0( 4 Votes )
Assume that each atom in a copper wire contributes one free electron. Estimate the number of free electrons in a copper wire having a mass of 6.4 g (take the atomic weight of copper to be 64 g mol–1).
Atomic weight of copper = 64 g mol-1
Mass of copper wire : m = 6.4 g
We know that,
Number of moles in 64 g of copper = 1
Thus, number of moles in 6.4 g of copper = 0.1
Number of atoms in one mole=NA
Here, NA is the Avogadro Number : NA = 6.023× 1023 atoms
∴No.of atoms in 0.1 mole of copper=0.1× 6.023× 1023
∴No.of atoms in 0.1 mole of copper=0.1× 6.023× 1022
It is given that each atom contributes one free electron,
Therefore in 0.1 mole of copper will contribute
Hence, there will be free electron in 6.4 g of copper.
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A. Derive the expression for electric field at a point on the equatorial line of an electric dipole.
B. Depict the orientation of the dipole in (i) stable, (ii) unstable equilibrium in a uniform electric field.
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