2101 Electric Charge

Two positive charges or two negative charges repel each other. A positive charge and a negative charge attract each other.

Electric charge and the structure of Matter

The structure of atoms can be described in terms of three particles: the negatively charged electron, the positively charged proton, and the uncharged neutron (Fig. 21.3).

Graph

Mass of electron me=9.109×10−31 kgm_e = 9.109 \times 10^{-31} \text{ kg}
Mass of proton mp=1.673×10−27 kgm_p = 1.673 \times 10^{-27} \text{ kg}
Mass of neutron mn=1.675×10−27 kgm_n = 1.675 \times 10^{-27} \text{ kg}

Electric charge is conserved

  • The algebraic sum of all the electric charges in any closed system is constant.
  • The magnitude of charge of the electron or proton is a natural unit of charge.

Exercises

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