Of the following transitions in hydrogen atom, the one which gives an absorption line of lowest frequency is:

1.  n = 1 to n = 2

2.  n = 3 to n = 8

3.  n = 2 to n = 1

4.  n = 8 to n = 3

Spin multiplicity of Ca $\left(1s^2<mspace\; width="1em"></mspace>2s^2<mspace\; width="1em"></mspace>2p^{6}3s^{2}3p^{6}4s^2\right)$ in ground state is 

1.  1 only

2.  2 only 

3.  Either 3 or 1

4.  3 only 

The total number of electron present in Cu Which have zero value of magnetic quantum number in the ground state

1. 13

2. 7

3. 8

4. 15

Which of the given graphs depicts the correct relation between the kinetic energy of photoelectrons and the frequency of incident light (v)?

1.          2.  

3.           4.  

The energy of a photon of wavelength l = 1 meter is (Planck's constant = 6.626 $\times$ ${10}^{-34}$ Js, speed of light $=<mspace\; width="1em"></mspace>3<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^5<mspace\; width="1em"></mspace>\mathrm{m}/\mathrm{s}$)

1.  1.988 x ${10}^{-25}<mspace\; width="1em"></mspace>\mathrm{J}$

2.  1.988 x ${10}^{-32}<mspace\; width="1em"></mspace>\mathrm{J}$

3.  1.988 x ${10}^{-28}<mspace\; width="1em"></mspace>\mathrm{J}$

4.  1.988 x ${10}^{-38}<mspace\; width="1em"></mspace>\mathrm{J}$

For a one-electron atom, the set of allowed quantum numbers is

1.  n = 1, l = 0, ${\mathrm{m}}_{\mathrm{l}}$ = 0, ${\mathrm{m}}_s$ = +1/2

2.  n = 1, l = 1, ${\mathrm{m}}_{\mathrm{l}}$ = 0, ${\mathrm{m}}_s$ = +1/2

3.  n = 1, l = 0, ${\mathrm{m}}_{\mathrm{l}}$ = -1, ${\mathrm{m}}_s$ = -1/2

4.  n = 1, l = 0, ${\mathrm{m}}_{\mathrm{l}}$ = 1, ${\mathrm{m}}_s$ = -1/2

A metal is irradiated with light of wavelength 660 nm. Given that the work function of the metal is I .0 eV. the de-Broglie wavelength of the ejected electron is close to

1.  6.6 x ${10}^{-7}$ m

2.  1.3 x ${10}^{-9}$ m

3.  8.9 x ${10}^{-11}$ m

4.  6.6 x ${10}^{-13}$ m

The energy of an electron in the first Bohr orbit is

1.  -30.6 eV

2.  -40.8 eV

3.  -54.4 eV

4.  +40.8 eV

When a certain metal was irradiated with light of frequency 3.2 x ${10}^{16}$ Hz, the photoelectrons emitted had twice the kinetic energy as did the photoelectrons emitted when the same metal Was irradiated with light of frequency 2.0 x ${10}^{16}$Hz The $v_0$ of the metal is

1.  2.4 x ${10}^{16}$ Hz

2.  8.0 x ${10}^{16}$Hz

3.  8.0 x ${10}^{15}$ Hz

4.  7.2 x ${10}^{16}$Hz

An electron beam can undergo diffraction by crystals which proves the wave nature Of electrons. The potential required for a beam Of electrons to be accelerated so that its wavelength becomes equal to 0.154 nm is

1.  63.5 V

2.  31.75 V

3.  635 V

4.  127 V