Practice question

Given: A photon’s energy is 3.0 eV . What is its momentum? (Take c = 3 × 10⁸ m/s, 1 eV = 1.6 × 10⁻¹⁹ J ) These values define the system as per NCERT data. Formula: E = 3.0 × 1.6 × 10⁻¹⁹= 4.8 × 10⁻¹⁹ J. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: For a photon, p = E/c = frac4.8 × 10⁻¹⁹³ × 10⁸= 1.6 × 10⁻²⁷ kg m/s . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.