The quantum numbers +$\frac{1}{2}$ and -$\frac{1}{2}$ for the electron spin represent

• rotation of the electron in clockwise and anticlockwise direction respectively

• rotation of the electron in anticlockwise and clockwise direction respectively

• magnetic moment of the electron pointing up and down respectively

• two quantum mechanical spin states which have no classical analogues

What is the wave number of 4^th line in Balmer series of hydrogen spectrum ? (R =1,09,677 cm^-1)

• 24630 cm^-1

• 24360 cm^-1

• 24730 cm^-1

• 24372 cm^-1

Heisenberg uncertainty principle can be explained as

• $∆\mathrm{x} \ge \frac{∆\mathrm{P} \times \mathrm{h}}{4\mathrm{\pi }}$

• $∆\mathrm{x} \times ∆\mathrm{P} \ge \frac{\mathrm{h}}{4\mathrm{\pi }}$

• $∆\mathrm{x} \times ∆\mathrm{P} \ge \frac{\mathrm{h}}{\mathrm{\pi }}$

• $∆\mathrm{P} \ge \frac{\mathrm{\pi h}}{∆\mathrm{x}}$

The de-Broglie wavelenght of a particle with mass 1 kg and velocity 100 m/s is

• 6.6 x 10^-33 m

• 6.6 x 10^-36 m

• 3.3 x 10³³ m

• 3.3 x 10^-36 m

Neutron is discovered by

• Chadwick

• Rutherford

• Yukawa

• Dalton

What is X in the following nuclear reaction?

₇N¹⁴ + ₁H¹ $\to$₈O¹⁵ + X

• ₀n¹

• _-1e⁰

• ₊₁e⁰

• $\mathrm{\gamma }$

The wavelength of a spectral line emitted by hydrogen atom in the Lyman series is $\frac{16}{15\mathrm{R}}\mathrm{cm}$.
The value of n, will be

                               [R=Rydberg constant]

• 1

• 2

• 3

• 4

Which of the following have maximum number of unpaired electrons ?

• Fe³⁺

• Fe²⁺

• Co²⁺

• Co³⁺

If magnetic quantum number of a given atom represented by -3, then what will be its principal quantum number ?

• 2

• 3

• 4

• 5

For an electron whose x-positional uncertainity is 1x 10^-10 m, the uncertainity in the x-component of the velocity in ms^-1 will be of the order of:

$(\mathrm{Data} : {\mathrm{m}}_{\mathrm{e}} = 9\times {10}^{-31} \mathrm{Kg} , \mathrm{h}= 6.6 \times 10{ }^{-34} \mathrm{JS} )$

• 10⁶

• 10³

• 10¹²

• 10¹⁵