Question

If 7.84 x 10^7 J of energy is released from a fusion reaction, what amount of mass in kilograms would be lost? Recall that c = 3 x 10^8 m/s.
7.06 x 10^24

8.71 x 10^-4

8.71 x 10^-7

8.71 x 10^-10

Answer 1

Use the formula
E=mc^2

plug the values,

The amount of mass in kilograms would be lost is 8.71 x 10^-10

Answer 2

Answer : The mass lost would be, $8.71\times 10^{-10}Kg$

Solution : Given,

Energy released = $7.84\times 10^{7}J=7.84\times 10^{7}\text{ Kg }m^2/s^2$

$(1J=1\text{ Kg }m^2/s^2)$

Speed of light 'c' = $3\times 10^{8}m/s$

Formula used :

$E=m\times c^2$

where,

E = energy

m = mass

c = speed of light

Now put all the given values in the above formula, we get

$7.84\times 10^{7}\text{ Kg }m^2/s^2=m\times (3\times 10^{8}m/s)^2$

$m=8.71\times 10^{-10}Kg$

Therefore, the mass lost would be, $8.71\times 10^{-10}Kg$