Answer:
4.74 x 10⁷ yr
Step-by-step explanation:
m = Rate of conversion of mass to energy by sun = 4 x 10⁹ kg/s
t = total time taken to convert mass of earth to energy
M = mass of earth = 5.98 x 10²⁴ kg
Using the equation
M = m t
5.98 x 10²⁴ = (4 x 10⁹) t
t = 1.495 x 10¹⁵ sec
we know that, 1 yr = 3.154 x 10⁷ sec
t = (1.495 x 10¹⁵ sec) (3.154 x 10⁷ sec)⁻¹ yr
t = 4.74 x 10⁷ yr