Embibe Experts Solutions for Chapter: Structure of Atom, Exercise 1: KVPY Aptitude Test - Stream SA 2016

A certain metal has a work function of $\Phi =2\mathrm{eV}$. It is irradiated first with $1 \mathrm{W}$ of $400\mathrm{nm}$ light and later with $1 \mathrm{W}$ of $800\mathrm{nm}$ light. Among the following, the correct statement is: [Given:Planck constant $\left(\mathrm{h}\right)$$=6.626\times {10}^{-34} {\mathrm{m}}^2{\mathrm{kgs}}^{-1}$ Speed of light $\left(\mathrm{c}\right)=3\times {10}^8 {\mathrm{ms}}^{-1}$]

The correct set of quantum numbers for the unpaired electron of $\mathrm{Cu}$ atom is :

Among the following, the correct statement about cathode ray discharge tube is

 

The correct statements among the following.

i. ${\mathrm{E}}_{2\mathrm{s}}\left(\mathrm{H}\right)>{\mathrm{E}}_{2\mathrm{s}}\left(\mathrm{Li}\right)<{\mathrm{E}}_{2\mathrm{s}}\left(\mathrm{Na}\right)>{\mathrm{E}}_{2\mathrm{s}}\left(\mathrm{K}\right)$
ii. The maximum number of electrons in the shell with principal quantum number $n$ is equal to $2n^2$
iii. Extra stability of half-filled subshell is due to smaller exchange energy.
iv. Only two electrons, irrespective of their spin, may exist in the same orbital are.

Among the following, the incorrect statement is

A $20 \mathrm{g}$ object is moving with velocity $100 {\mathrm{ms}}^{-1}$. The de Broglie wavelength (in $\mathrm{m}$) of the object is [Planck's constant $\mathrm{h}=6.626\times {10}^{-34} \mathrm{J} \mathrm{s}$]

The maximum nuber of electrons that can be filled in the shell with the principal quantum number $\mathrm{n}=3$ is

The photoelectric behaviour of $\mathrm{K}, \mathrm{Li}, \mathrm{Mg}$ and $\mathrm{Ag}$ metals is shown in the plot below. If light of wavelength $400 \mathrm{nm}$ is incident on each of these metals, which of them will emit photoelectrons? [Planck's contant $h=6.626\times {10}^{-34}\mathrm{Js}$; velocity of light $c=3\times {10}^8 {\mathrm{ms}}^{-1}; 1\mathrm{eV}=1.6\times {10}^{-19} \mathrm{J}$]