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If m → a , m → b and m → c are 3 unit vectors such that m → a ⋅ m → b = 0 , m → a ⋅ m → c = 0 and the angle between m → b and m → c is π 3 , then the value of m → a × m → b - m → a × m → c is equal to

Options

  1. A1
  2. B2
  3. C3
  4. D4

Correct answer

A. 1

Step-by-step solution

∵ m → a ⋅ m → b = 0 , m → a ⋅ m → c = 0 ⇒ m → a ⋅ m → b - m → c = 0 ⇒ m → a is perpendicular to m → b - m → c Therefore, m → a × m → b - m → c = m → a m → b - m → c = 1 × 1 + 1 - 2 × 1 × 1 × cos π 3 = 1

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