In \(_{35}^{80}Br\), $$the number of protons, neutrons, and electrons are:${}_{\mathrm{}}{}^{\mathrm{}}$

1. 25, 45, 45

2. 35, 45, 35

3. 45, 45, 35

4. 80, 35, 35

The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. The proper symbol of the species is :

The Vividh Bharati station of All India Radio, Delhi, broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter and the part of the electromagnetic spectrum does it belong are :

A yellow radiation having wavelength 5800 Å. The wavenumber (a) and frequency (b) of yellow radiation are respectively-
1. \(\mathrm{a   = 172.4   \times   10^{4}    ~ cm^{- 1} ,   b   =   5 . 172   \times   10^{14} ~  s^{- 1}}\)
2. \(\mathrm{a   =   5 . 172   \times   10^{14} ~  s^{- 1} ,   b   = 17.24   \times   10^{4}   ~  cm^{- 1}}\)
3. \( \mathrm{a   =   724   \times  10^{5}  ~   cm^{- 1} ,   b   =   5 . 172   \times   10^{15} ~  s^{- 1}}\)
4. \(\mathrm{a   = 1.72 4   \times   10^{4}   ~ cm^{- 1} ,   b   =   5 . 172   \times   10^{14} ~ s^{- 1}}\)

The frequency of one photons is 5 × 10¹⁴ Hz. The energy of one mole of photons of radiation is :

1. 177.51 kJ mol^–1

2. 188.51 kJ mol^–1

3. 199.51 kJ mol^–1

4. 291.61 kJ mol^–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$0.12 \times {10}^{21} {\mathrm{s}}^{-1}$

When electromagnetic radiation of wavelength 300 nm falls on the surface of sodium, electrons are emitted with a kinetic energy of 1.68 ×10⁵ J mol^–1. The minimum energy needed to remove an electron from sodium and the maximum wavelength that will cause a photoelectron to be emitted are, respectively:

1. 2.31 × 10⁵ J mol^–1, 517 nm

2. 23.1 × 10⁵ J mol^–1, 517 nm

3. 3.31 × 10⁵ J mol^–1, 417 nm

4. 33.1 × 10⁵ J mol^–1, 417 nm

The threshold frequency ν_o for a metal is 7.0 ×10¹⁴ s^–1. The kinetic energy of an electron emitted when radiation of frequency ν =1.0 ×10¹⁵ s^–1 hits the metal, is-

1. 19.88 ×10^–19 J

2. 1.988 ×10^–19 J

3. 1.988 ×10^–20 J

4. 19.88 ×10^–17 J

The frequency and wavelength of a photon emitted during a transition from n = 5 state to the n = 2 state in the hydrogen atom  are respectively :

1.  \(6.91\times10 ^{14} Hz\);   543 nm

2. \(7.91\times10 ^{14} Hz\); 434 nm

3. \(6.91\times10 ^{14} Hz\); 434 nm 

4. \(7.91\times10 ^{14} Hz\); 343 nm

The energy and the radius of the first orbit of He⁺ are respectively :

1. \(-8.72\times 10^{-18}J\); 0.02645 nm

2. \(8.72\times 10^{-18}J\); 0.02645 nm

3. \(-7.82\times 10^{-18}J\) ; 0.03655 nm

4. \(7.82\times 10^{-18}J\); 0.03655 nm