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

Answer : The mass lost would be,
`8.71* 10^(-10)Kg`

Solution : Given,

Energy released =
`7.84* 10^(7)J=7.84* 10^(7)\text{ Kg }m^2/s^2`

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

Speed of light 'c' =
`3* 10^(8)m/s`

Formula used :

`E=m* 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* 10^(7)\text{ Kg }m^2/s^2=m* (3* 10^(8)m/s)^2`

`m=8.71* 10^(-10)Kg`

Therefore, the mass lost would be,
`8.71* 10^(-10)Kg`

Answer 2

Use the formula
E=mc^2

plug the values,

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