20. The work function ( $\phi$ ) of some metals is listed below. The number of metals which will show photoelectric effect when light of 300 nm wavelength falls on the metal is

\begin{center}
\begin{tabular}{ | l | c | c | c | c | c | c | c | c | c | }
\hline
Metal & Li & Na & K & Mg & Cu & Ag & Fe & Pt & W \\
\hline
$\phi ( \mathrm { eV } )$ & 2.4 & 2.3 & 2.2 & 3.7 & 4.8 & 4.3 & 4.7 & 6.3 & 4.75 \\
\hline
\end{tabular}
\end{center}

\section*{ANSWER: 4}
\begin{enumerate}
  \setcounter{enumi}{20}
  \item To an evacuated vessel with movable piston under external pressure of $1 \mathrm {~atm} . , 0.1 \mathrm {~mol}$ of He and 1.0 mol of an unknown compound (vapour pressure 0.68 atm . at $0 ^ { \circ } \mathrm { C }$ ) are introduced. Considering the ideal gas behaviour, the total volume (in litre) of the gases at $0 ^ { \circ } \mathrm { C }$ is close to
\end{enumerate}

\section*{ANSWER:7}
\begin{enumerate}
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  \item The total number of alkenes possible by dehydrobromination of 3-bromo-3-cyclopentylhexane using alcoholic KOH is
\end{enumerate}

\section*{ANSWER: 5}
\begin{enumerate}
  \setcounter{enumi}{22}
  \item A decapeptide (Mol. Wt. 796) on complete hydrolysis gives glycine (Mol. Wt. 75), alanine and phenylalanine. Glycine contributes $47.0 \%$ to the total weight of the hydrolysed products. The number of glycine units present in the decapeptide is
\end{enumerate}

ANSWER: 6

\section*{PART II: PHYSICS}
\section*{SECTION-I (Total Marks : 21)}
\section*{(Single Correct Answer Type)}
This section contains 7 multiple choice questions. Each question has four choices (A), (B), (C) and (D) out of which ONLY ONE is correct.\\