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
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. | 4. |
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 |
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
2.
3.
4. 2
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 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
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