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#attraction

2 public questions tagged with this topic.

Potential Energy of System of Charges

In a system where a charged conductor is placed near an uncharged conductor, why does the uncharged conductor experience

**System of charges** potential energy is sum over pairs U = Σ k q_i q_j/r_ij, work required to assemble charges from infinity. For 28 μC and -14 μC, 0.28 m apart, U=9×10⁹×28×(-14)×10⁻¹²/0.28= -12.6 J, negative indicates bound system. The charged conductor induces charges on the uncharged conductor: opposite charges on the near side and like charges on the far side. The distance between the opposite charges is smaller than between like charges, so the attractive force (proportional to 1/r² ) between opposite charges dominates over the repulsive force between like charges. This imbalance result

Ref: NCERT > Physics Book > Electrostatic Potential and Capacitance > Potential Energy of System of Charges

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Sea urchin -lll

Resact specifically attracts:

Resact is fourteen amino acid peptide purified from egg jelly of Arbacia punctulata that guides sperm chemotaxis toward egg. It binds high-affinity receptors on sperm flagellum coupled to guanylate cyclase, increasing cGMP and calcium oscillations altering flagellar waveform and steering toward gradient source. Chemotactic response is highly selective; Arbacia sperm respond strongly to Resact at picomolar concentrations, while Strongylocentrotus sperm show minimal response, preferring Speract. This species specificity enhances conspecific fertilization assurance when multiple species spawn sim

Ref: Ward et al., Chemotaxis: Resact species-specific attraction conspecific sperm sea urchin reproductive isolation.

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