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Energy Released in Proton Bombardment of Lithium

The energy released when 717.13 kg\frac{7}{17.13}\text{ kg} of 37Li_3^7\text{Li} is converted into 24He_2^4\text{He} by proton bombardment is α×1032 eV\alpha \times 10^{32}\text{ eV}. The value of α\alpha is ________. (Nearest integer) (Mass of 37Li=7.0183 u_3^7\text{Li} = 7.0183\text{ u}, mass of 24He=4.004 u_2^4\text{He} = 4.004\text{ u}, mass of proton =1.008 u= 1.008\text{ u} and 1 u=931 MeV/c21\text{ u} = 931\text{ MeV}/c^2 and Avogadro number =6.0×1023= 6.0 \times 10^{23})

Official Numerical Answer6

Topics & Concepts

NucleiNuclear Reactions

Step-by-Step Solution

The reaction for the conversion of 37Li_3^7\text{Li} into 24He_2^4\text{He} by proton bombardment is given by: 11H+37Li24He+24He_1^1\text{H} + _3^7\text{Li} \rightarrow _2^4\text{He} + _2^4\text{He}

Step 1: Calculate the mass defect (Δm\Delta m) for a single reaction. Δm=[m(11H)+m(37Li)]2m(24He)\Delta m = \left[ m(_1^1\text{H}) + m(_3^7\text{Li}) \right] - 2 \cdot m(_2^4\text{He})

Substitute the given values of masses: Δm=(1.008+7.0183)2×4.004\Delta m = (1.008 + 7.0183) - 2 \times 4.004 Δm=8.02638.008=0.0183 u\Delta m = 8.0263 - 8.008 = 0.0183\text{ u}

Step 2: Calculate the energy released (QQ) per reaction. Q=Δm×931 MeVQ = \Delta m \times 931\text{ MeV} Q=0.0183×931 MeV=17.0373 MeV=17.0373×106 eVQ = 0.0183 \times 931\text{ MeV} = 17.0373\text{ MeV} = 17.0373 \times 10^6\text{ eV}

Step 3: Calculate the total number of 37Li_3^7\text{Li} nuclei (NN). The mass of Lithium provided is m=717.13 kg=700017.13 gm = \frac{7}{17.13}\text{ kg} = \frac{7000}{17.13}\text{ g}. Since the molar mass of 37Li_3^7\text{Li} is 7 g/mol7\text{ g/mol}:

N=mM×NAN = \frac{m}{M} \times N_A N=700017.137×6.0×1023N = \frac{\frac{7000}{17.13}}{7} \times 6.0 \times 10^{23} N=100017.13×6.0×1023=6.0×102617.13 nucleiN = \frac{1000}{17.13} \times 6.0 \times 10^{23} = \frac{6.0 \times 10^{26}}{17.13}\text{ nuclei}

Step 4: Calculate the total energy released (EE). E=N×QE = N \times Q E=(6.0×102617.13)×(17.0373×106 eV)E = \left(\frac{6.0 \times 10^{26}}{17.13}\right) \times \left(17.0373 \times 10^6\text{ eV}\right) E=6.0×17.037317.13×1032 eVE = \frac{6.0 \times 17.0373}{17.13} \times 10^{32}\text{ eV} E=102.223817.13×1032 eV5.9675×1032 eVE = \frac{102.2238}{17.13} \times 10^{32}\text{ eV} \approx 5.9675 \times 10^{32}\text{ eV}

Comparing with E=α×1032 eVE = \alpha \times 10^{32}\text{ eV}: α5.9675\alpha \approx 5.9675

Rounding off to the nearest integer, we get: α=6\alpha = 6

Energy Released in Proton Bombardment of Lithium | Physics PYQ Solution - JEE Challenger