Question

Four physical quantities are listed in Column I. Their values are listed in Column II in a random order.

Column I	Column II
p. Thermal energy of air molecules at room temperature	(i) 0.02 eV
q. Binding energy of heavy nuclei per nucleon	(ii) 2 eV
r. X-ray photon energy	(iii) 10 keV
s. Photon energy of visible light	(iv) 7 MeV

The correct matching the Column I and Column II is given by

• A. $p\to i,q\to iv,r\to iii,s\to ii$
• B. $p\to i,q\to iii,r\to ii,s\to iv$
• C. $p\to ii,q\to i,r\to iii,s\to iv$
• D. $p\to ii,q\to iv,r\to i,s\to iii$

Answer 1

The correct option is A $p\to i,q\to iv,r\to iii,s\to ii$

p) : Thermal energy of the air molecules at room temperature $E_{thermal}\approx KT=1.38\times {10}^{-23}\times 300J=4.14\times {10}^{-21}J=0.259eV$ (approx)

q) : The graph of binding energy per nucleon vs mass number suggests that the binding energy per nucleon of heavy atom lies between $7$ to $8MeV$

r) : X-Rays have wavelength in the range from $0.01nm$ to $10nm$, $⟹$ These have energy range of $\approx 100eV$ to $100keV$

s) : Visible light have wavelength $\approx 380nm$ to $780nm$ which implies that these have energy range $1.6eV$ to $3.3eV$