Velocity of helium atom at 300 K is 2.40 x 10² meter per sec. What is its wavelength? (mass number of helium is 4) -

1. 0.416 nm

2. 0.83 nm

3. 803 Å

4. 8000 Å

The de-Broglie wavelength of a particle having the momentum of
3.3 x 10^-24 kg m s^-1 will be;

1. 0.002 Å

2. 0.02 Å

3. 0.2 Å

4. 2Å

Which of the following statements is not true with respect to photoelectric effect -

1. The plot of kinetic energy of the photoelectrons against frequency of absorbed radiation gives a straight line parallel to x-axis

2. The plot of K.E. of the photoelectrons against frequency of absorbed radiation gives a straight line with slope equal to h and intercept to work function of metal

3. The plot of kinetic energy of the photoelectrons versus the intensity of incident radiation with constant frequency gives a straight line parallel to x-axis

4. When intensity of light is increased the number of photons ejected increases but the energies of these electrons are the same.

The first line in the Lyman series in the spectrum of hydrogen atom occurs at a wavelength of 1215 Å and the limit for Balmer series is 3645 Å. Calculate the wavelength corresponding to series limit of Lyman series.

1. 911.2 Å

2. 812.2 Å

3. 712.2 Å

4. 678.4 Å

The correct order of increasing energy of atomic orbital is: 

1. 3s, 3p, 4s, 3d, 4p

2. 3s, 3p, 3d, 4s, 4p

3. 3s, 3p, 4s, 4p, 3d

4. 3s, 3p, 3d, 4p, 4s

In Rutherford's alpha scattering experiment using gold foil, the kinetic energy of the alpha particle was 1.2 x 10^-12J. For a head on collision, using the formula K.E. = $\frac{1}{4{\mathrm{\pi \epsilon }}_0}$x 2Ze²/r₀ , what may be the magnitude of r₀ [ The nuclear radius of gold, Z=79; $\frac{1}{4{\mathrm{\pi \epsilon }}_0}$= 9 x 10⁹ new-ton/meter² coulomb^-2, e= 1.6x10^-19 coulomb]

1. 3 x 10^-14m

2. 1.3 x 10^-14m

3. 2.1 x 10^-14m

4. 4.3 x 10^-14m

The quantum number of the most energetic electron in an Ne atom in the first excited state is

The frequency of line spectrum of sodium is 5.09 x 10¹⁴ sec^-1. Its wavelength (in nm) will be -[C= 3x10⁸m/sec]

1. 510nm

2. 420nm

3. 589nm

4. 622nm

The total number of neutrons in dipositive zinc ions with mass number 70 is -

1. 34

2. 40

3. 36

4. 38

With a certain exciting radiation of a particular frequency, to which hydrogen atoms are exposed, the maximum number of spectral lines obtainable in the emission is 15. The uppermost energy level to which the electron is excited is 

1. 4

2. 5

3. 6

4. 7