3. Mass equivalent of 931 MeV energy is

(a) 6.02× 10^{-23} kg | **(b) 1.766× 10**^{-27} kg | (c)2.67× 10^{-28} kg | (c) 6.02× 10^{-27} kg |

**Solution:** Use Einstein equation to convert energy to mass. E = mc^{2}. Put values,

931× 10^{6} × 1.602 2× 10^{-19} = m × (3×10^{8})^{2}

⇒ m = (931 × 1.6022 × 10^{6} × 10^{-19})/(3× 10^{8})^{2}

⇒ m = (931 × 1.6022/9) × 10^{6-19-16} = 1491.6482/9 × 10^{-29}

⇒ m = 165.73 × 10^{-29} kg = 1.6573 × 10^{-27} kg

(Do you know where from the 1.6022 × 10^{-19} come?)

Pingback:Physics 12 – msa

1ev=1.6022×10^-19j

Seerat AnjumYes, exactly.