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Two positive ions, each carrying a charge q, are separated by a distance d. If F is the force of repulsion between the ions, the number of electrons missing from each ion will be (e being the charge on an electron)

Asked in CBSE AIPMT 2010 · Properties of charge

• (1) (4πε₀ Fd²)/(e²)
• (2) √(4πε₀ Fe²)/(d²)
• (3) √(4πε₀ Fd²)/(e²)
• (4) (4πε₀ Fd²)/(q²)

Step-by-step solution

Why the other options are wrong

• (1) This is n², not n; the square root has not been taken.
• (2) Swaps d and e inside the root, which also leaves the expression with the wrong dimensions.
• (4) Answers in terms of q, which is the very quantity being counted; the result must be built from F, d and e alone.

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