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SarkariResultOutBMS · 2024

Previous Year Question

Point charges Q1 = 1 nC and Q2 = 2 nC are at a distance apart. Given the following statementsStatement 1:As the distance between them decreases, the force on Q1 increases linearly.Statement 2:The force on Q2 is the same in magnitude as that on Q1.Choose the correct option for the above statements
  1. Statement 1 is true, but statement 2 is false
  2. Both statements 1 and 2 are false
  3. Statement 1 is false, but statement 2 is true
  4. Both statements 1 and 2 are true

Correct answer: C

Explanation

Coulomb force magnitude is F=(1/4πε)Q1Q2/r². Reducing separation therefore increases force with the inverse square of distance, not linearly. Force on Q1 and Q2 has equal magnitude and opposite direction by Newton’s third law. The correct statement combination is option C.

Formula

F=(1/4πε)Q1Q2/r²

Step-by-step solution

Force Between Point Charges explanatory diagram

Correct Answer

C — Statement 1 is false, but statement 2 is true

Concept and Reasoning

Coulomb force magnitude is F=(1/4πε)Q1Q2/r². Reducing separation therefore increases force with the inverse square of distance, not linearly. Force on Q1 and Q2 has equal magnitude and opposite direction by Newton’s third law. The correct statement combination is option C.

Calculation / Key Relation

F=(1/4πε)Q1Q2/r²

Exam Takeaway

Coulomb force follows 1/r² and mutual forces are equal/opposite.

Common Mistake

Do not describe force increase as linear when distance changes.

Common mistake

Do not describe force increase as linear when distance changes.

Exam tip

Coulomb force follows 1/r² and mutual forces are equal/opposite.

Quick method

Coulomb force follows 1/r² and mutual forces are equal/opposite.