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

A particular station of All India Radio, New Delhi, broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is: [speed of light, $\mathrm{c}=3.0\times {10}^8$ ${\mathrm{ms}}^{-1}$]

A 100-watt bulb emits monochromatic light of wavelength 400 nm. The number of photons emitted per second by the bulb is :

1. 4$0.12 \times {10}^{20} {\mathrm{s}}^{-1}$

2. $2.012 \times {10}^{21} {\mathrm{s}}^{-1}$

3. $2.012 \times {10}^{20} {\mathrm{s}}^{-1}$

4. 2$0.12 \times {10}^{21} {\mathrm{s}}^{-1}$

The mass of a photon with wavelength 3.6 Å is :

A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm, the other is at:

1. 1035 nm

2. 325 nm

3. 743 nm

4. 518 nm

The number of electrons that can be present in the subshells having m_s value of \(-\frac{1}{2}\) for n = 4 are:

If the position of the electron were measured with an accuracy of +0.002 nm, the uncertainty in the momentum of the electron would be: 

1. 5.637 × 10^–23 kg m s^–1

2. 4.637 × 10^–23 kg m s^–1

3. 2.637 × 10^–23 kg m s^–1

4. 3.637 × 10^–23 kg m s^–1

1. 32.22 × 10^–16 J

2. 12.22 × 10^–16 J

3. 22.27 × 10^–16 J

4. 31.22 × 10^–16 J
 

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.