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Current Electricity — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsCurrent Electricity1 Mark
Question
For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is not the correct explanation of A.
  3. A is true, but R is false.
  4. A is false, and R is also false.
Assertion: Current is a scalar quantity.
Reason: Electric current arises due to continuous flow of charged particles or ions.
✓

Answer

  1. Both A and R are true, but R is not the correct explanation of A.
Explanation:
Current is a scalar quantity, it is justified by the following two observations:
  1. If current carrying wire is bent at some point, then also current in the wire remains same, while a vector quantity always changes by changing its direction.
  2. Current flowing in the circuit do not follow the laws of vector addition. It follows according to ordinary rule of algebra. This makes it clear that current is not a vector but a scalar quantity. Also current is defined as rate of flow of charge through the wire $\text{I}=\frac{\text{dq}}{\text{dt}}.$

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