1. 0^° 2. 90^° 3. 45^° 4. 180^°

Answer: 2. 90^° Key idea: |vec A+vec B|²=A²+B²+2ABcosθ and |vec A-vec B|²=A²+B²-2ABcosθ . Setting them equal gives 4ABcosθ=0 , so cosθ=0 and θ=90^° .

If the magnitude of sum of two vectors is equal to the magnitude of difference of the two vectors, the angle between these vectors is :

1. \(0^\circ\)

2. \(90^\circ\)

3. \(45^\circ\)

4. \(180^\circ\)

Doubtly Asked 30 Oct 2026 NEET UG 2016 Phase 1 Practice test neet Save WhatsApp Report

Best answer

Answer: 2. \(90^\circ\)

Key idea: \(|\vec A+\vec B|^2=A^2+B^2+2AB\cos\theta\) and \(|\vec A-\vec B|^2=A^2+B^2-2AB\cos\theta\).

Setting them equal gives \(4AB\cos\theta=0\), so \(\cos\theta=0\) and \(\theta=90^\circ\).

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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