Assertion and reason: circuits

Exercise and reference answers

Questions

1. Reason

   At the null point the four resistances satisfy a fixed ratio.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   A Wheatstone bridge can measure an unknown resistance.

2. Reason

   Charge cannot accumulate at a junction in a steady current.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Kirchhoff's junction rule follows from conservation of charge.

3. Reason

   Kirchhoff's loop rule sums potential changes to zero.

   Verdict

   Both are true; the reason does not explain the assertion.

   Assertion

   Metals have low resistivity.

Explanation