# Environmental Science: Numerical Questions – Energy (Nuclear Fission)

Doorsteptutor material for UGC is prepared by world's top subject experts: Get detailed illustrated notes covering entire syllabus: point-by-point for high retention.

## Nuclear Fission

Q 1 A typical fission reaction involving an atom of_{92}U^{235} leads to a mass defect kg. How much energy is going to be released by 1.0 g of_{92}U^{235}?

(1) 3.33 × 10 ^{− 11} MJ

(2) 2.23 × 10^{12} MJ

(3) 2.56 × 10^{4} MJ

(4) 8.53 × 10^{4} MJ

Answer: Option (4) 8.53 × 10^{4} MJ

Mass Defect = 0.37 × 10 − 27 kg

Amount of_{92}U^{235} = 1 gm

E = mc^{2}

Number of Atoms in 5 gm of_{92}U^{235} = nA

=

=

=

Total Energy = Energy of 1 atom Number of Atoms

Q 2 In a nuclear fission reaction involving ^{235}U_{92} and a slow neutron, the mass defect is found to be 0.223 U. How much energy will be released from 5.0 gram of ^{235}U_{92}?

(1) 426.7 GJ

(2) 85.3 GJ

(3) 170.6 GJ

(4) 42.6 GJ

Answer: Option (1) 426.7 GJ

Mass Defect = 0.223 u

Amount of_{92}U^{235} = 5 gm

Mass Defect

E = mc^{2}

Total Energy Released from 5 gm of ^{92}U = nA mc^{2}

n = number of moles

A = Avogadro՚s number

= 437.19 GJ

-Mayank