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Electric Charges and Fields — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsElectric Charges and Fields1 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 (A): A small metal ball is suspended in a uniform electric field with an insulated thread. If high-energy X-ray beam falls on the ball, the ball will be deflected in the electric field.
Reason (R): X-rays emits photoelectron and metal becomes negatively charged.
✓

Answer

  1. A is true but R is false.

Explanation:

When high energy X-ray beam falls on the ball, the metal will emit photoelectrons, thus leaving the positive charge on the ball. As a result of this, ball is deflected in the direction of the electric field.

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