In the SI system, what are the fundamental units of momentum?
A. kg m s⁻²
B. kg m² s⁻¹
C. kg² m s⁻¹
D. kg m s⁻¹
Answer: Option D
Solution (By JKSSB Mock Tests)
Momentum (p) is defined as the product of mass (m) and velocity (v). p = m × v. The SI unit of mass is the kilogram (kg) and the SI unit of velocity is meters per second (m/s or m s⁻¹). Therefore, the SI unit of momentum is kg m/s or kg m s⁻¹.
Explanation:
Magnetic field intensity (H) and magnetic field (B) are vectors. Magnetic flux is scalar (Φ = B·A). Resistance scalar, potential scalar. Vector quantities have direction. Current has direction but adds by scalar law, considered tensor sometimes but in basic physics not vector.
Explanation:
According to Newton's Second Law of Motion, the rate of change of momentum is directly proportional to the applied unbalanced force. Rate of change of momentum = Force = mass × acceleration. Force = 2 kg × 5 m/s² = 10 Newtons (N). Note that '10 kg m/s' is a unit of momentum, not its rate of change.
Explanation:
Refractive index n = c/v, where c = 3×10⁸ m/s (vacuum speed). Thus v = c/n = 3×10⁸ / 1.5 = 2×10⁸ m/s. This direct calculation tests optics fundamentals. Memory aid: 'Higher n ⇒ slower light; v = c/n'. Competitive exams frequently test this with common refractive indices. Always use c = 3×10⁸ m/s unless specified; verify units (m/s). This problem assesses basic formula application skills essential for wave optics sections.
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