A certain particle carries 2.5 × 10^–16 C of static electric charge. The number of electrons present in it would be:

Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm.

The frequency (ν) and wave number of this yellow light would be, respectively:

1. 517 x 10¹⁴ s^-1 , 172 x 10⁶ m^-1

2. 6.17 x 10¹⁴ s^-1 , 1.72 x 10⁶ m^-1

3. 4.17 x 10¹⁴ s^-1 , 2.72 x 10⁶ m^-1

4. 5.17 x 10¹⁴ s^-1 , 1.72 x 10⁶ m^-1

In Rutherford's experiment, generally, the thin foil of heavy atoms like gold, platinum, etc. have been used to be bombarded by the α-particles.

 If the thin foil of light atoms like aluminum etc. is used in Rutherford’s experiment, the difference that would be observed from the above results is :

1. The same results will be observed.

2. More deflection would be observed.

3. There will not be enough deflection.

4. None of the above.

The maximum number of neutrons are present in the nuclei of

$1.$ ${\mathrm{O}}_8^{16}$
$2.$ ${\mathrm{Mg}}_{12}^{24}$
$3.$ ${\mathrm{Fe}}_{26}^{56}$
$4.$ ${\mathrm{Sr}}_{38}^{88}$

The number of protons, neutrons and electrons in  \( _{71}^{175}Lu\) respectively, are:

1. 104, 71 and 71

2. 71, 71 and 104

3. 175, 104 and 71

4. 71, 104 and 71

The electron of a Br atom that experiences the lowest effective nuclear charge is:

1. 2p and 3p

2. 4p

3. 2p

4. 3p

Which among the following are isoelectronic species?

1. ${\mathrm{Na}}^{+}, {\mathrm{K}}^{+}, {\mathrm{Ca}}^{2+}, {\mathrm{Mg}}^{2+}$

2. ${\mathrm{Ca}}^{2+}, {\mathrm{Mg}}^{2+}, {\mathrm{S}}^{2-}, {\mathrm{K}}^{+}$

3. ${\mathrm{Ca}}^{2+}, \mathrm{Ar}, {\mathrm{S}}^{2-}, {\mathrm{K}}^{+}$

4. None of the above

The energy of the photon with a frequency of 3×10¹⁵ Hz is :

1. 1.988 × ${10}^{-18}$ J
2. 1.588 × ${10}^{-18}$ J
3. 1.288 × ${10}^{-18}$ J
4. 2.988 × ${10}^{-18}$ J

Match the following:

If the photon detector receives a total of 3.15$\times {10}^{-18}$ J from the radiation of 600 nm,
the number of photons received by the detector would be: 

$1.$ ${10}^2$
$2.$ $10$
$3.$ $50$
$4.$ $20$