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

1. 25, 45, 45

2. 35, 45, 35

3. 45, 45, 35

4. 80, 35, 35

Subtopic:  Number of Electron, Proton & Neutron |
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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 :

1. \(_{16}^{32}S^{2-}\) 2. \(_{18}^{32}S^{2-}\)
3. S816 4. S1632
Subtopic:  Number of Electron, Proton & Neutron |
 83%
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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 :

1. 319.3, Microwave 2. 219.3, Radiowave
3. 219.3, Ultraviolet Wave 4. 249.3, Radiowave
Subtopic:  Planck's Theory |
 73%
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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. \(\mathrm{a   = 1.72 4   \times   10^{4}   ~ cm^{- 1} ,   b   =   5 . 172   \times   10^{14} ~ s^{- 1}}\)

Subtopic:  Electromagnetic Radiation |
 55%
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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

Subtopic:  Planck's Theory |
 66%
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A 100-watt bulb emits monochromatic light of wavelength 400 nm. The number of photons emitted per second by the bulb is :

1. 40.12 × 1020 s-1

2. 2.012 × 1021 s-1

3. 2.012 × 1020 s-1

4. 20.12 × 1021 s-1

Subtopic:  Photo Electric Effect |
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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

Subtopic:  Photo Electric Effect |
 54%
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The threshold frequency νo 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

Subtopic:  Photo Electric Effect |
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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

Subtopic:  Hydrogen Spectra |
 56%
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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

Subtopic:  Hydrogen Spectra |
 80%
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