NEET Practice Questions (MCQs) with Answers & Solutions

(d) Energy / day = $200\times {10}^6\times 24\times 3600$

$=2\times 2.4\times 3.6\times {10}^{12}=1728\times {10}^{10} \mathrm{J}$

(c) $\mathrm{E}=∆{\mathrm{mc}}^2={10}^{-6}\times {\left(3\times {10}^8\right)}^2=9\times {10}^{10} \mathrm{J}$

(c) The average binding energy per nucleon = 8 MeV

(c) Mass of ${}_1\mathrm{H}_2$ = 2.01478 a.m.u
Mass of ${}_2\mathrm{He}_4$ = 4.00388 a.m.u
Mass of two deuterium = 2$\times$0.1478=4.02956
Energy equivalent to 2${}_1\mathrm{H}_2$

= 4.02956$\times$1.112 MeV=4.48 MeV

Energy equivalent to ${}_2\mathrm{He}_4$
= 4.00388$\times$7.047 MeV = 28.21 MeV
Energy released = 28.21-4.48 = 23.73 MeV = 24 MeV

(c) Energy released while forming a nucleus is known as binding energy (by definition).

(d) Isobars have equal mass numbers.

(c) Equivalent energy of 1 a.m.u mass = 931.5 MeV

(b) Q = $4\left(x_2-x_1\right)$

(a) Rest energy of an electron = ${\mathrm{m}}_{\mathrm{e}}{\mathrm{c}}^2$
Here ${\mathrm{m}}_{\mathrm{e}}=9.1\times {10}^{-31} \mathrm{kg}$ and c = velocity of light
$\therefore$ Rest energy = $9.1\times {10}^{-31}\times {\left(3\times {10}^8\right)}^2$ joule
$=\frac{9.1\times {10}^{-31}\times (3\times {10}^8{)}^2}{1.6\times {10}^{-19}}\mathrm{eV}=510 \mathrm{keV}$

(b) ${}_{z}X_A={}_{88}\mathrm{Ra}_{226}$
Number of protons = Z = 88
Number of neutrons = A-Z = 226-88 = 138.