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CUET · PHYSICS · PYQ PAPER 2023

The magnitude of electric force exerted by a proton on an electron in a hydrogen atom is, (Given distance of separation between charges, 1 \( \text{\AA} \))

  1. A \( 2.3 \times 10^{-10} \text{ N} \)
  2. B \( 2.3 \times 10^{-8} \text{ N} \)
  3. C \( 2.3 \times 10^{-9} \text{ N} \)
  4. D \( 2.3 \times 10^{-7} \text{ N} \)
Verified Solution

Answer & Solution

Correct Answer

(B) \( 2.3 \times 10^{-8} \text{ N} \)

Step-by-step Solution

Detailed explanation

\( r = 1 \text{ Å} = 1 \times 10^{-10} \text{ m} \) \( F = k \frac{|q_1 q_2|}{r^2} \) \( F = (8.9875 \times 10^9 \text{ N m}^2/\text{C}^2) \frac{(1.602 \times 10^{-19} \text{ C})^2}{(1 \times 10^{-10} \text{ m})^2} \) \( F \approx 2.3 \times 10^{-8} \text{ N} \)