AMU = atomic mass unit, proton=1 AMU ( 1 AMU also equals 1.67x10-27kgs)
Mass of 4 H atoms: 4x1.007825=4.03130AMU
Mass of He atom: 4.00268AMU
Difference: 0.02862AMU = 0.71% of original mass
If 4 grams (1/8 ounce) of H are converted to He, 2.8x10-3 grams are converted to energy:
E=(2.8x10-3grams)x c2 =2.8x10-6 kgs x(3x108m/sec)2
=2.6x1011 joules or enough to keep
a 60-watt light bulb shining for over 100 years