Q. No.The energies E1 and E2 of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e., and will be:
1.
2.
3.
4.
1. 25
2. 50
3. 75
4. 10
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
Which of the following is the correct symbol, when the number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively?
| 1. | \(_{16}^{32}S^{2-}\) | 2. | \(_{18}^{32}S^{2-}\) |
| 3. | 4. |
Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. The work function (W0) of the metal is:
1. 3.109 × 10–20 J
2. 2.922 × 10–19 J
3. 4.031 × 1019 J
4. 2.319 × 10–18 J
Match types of wave in Column-I with the corresponding frequency in Column-II and mark the appropriate option:
|
Column-I
(Types of Wave)
|
Column-II (Corresponding Frequency) |
||
| A. | X-rays | I. | |
| B. | Ultraviolet wave (UV) | II. | |
| C. | Long radio waves | III. | |
| D. | Microwave | IV. |
| A | B | C | D | |
| 1. | IV | I | III | II |
| 2. | I | IV | II | III |
| 3. | I | IV | III | II |
| 4. | IV | III | I | II |
A monochromatic infrared range finder of power 1milli watt emits photons with wavelength 1000 nm in 0.1 second. The number of photons emitted in 0.1 second is:
(Given: h = \(6.626 \times 10^{-34} J~s\) , c = \(3 \times 10^8 m~s^{-1}, \) Avogadro number = \(6.022 \times 10^{23}\))
1. \(30 \times 10^{37}\)
2. \(5 \times 10^{14} \)
3. \(30 \times 10^{34} \)
4. \(5 \times 10^{11} \)
Which of the following statement is not correct about the characteristics of cathode rays?
| 1. | They start from the cathode and move towards the anode |
| 2. | They travel in straight line in the absence of an external electrical or magnetic field |
| 3. | Characteristics of cathode rays do not depend upon the material of electrodes in cathode ray tube |
| 4. | Characteristics of cathode rays depend upon the nature of gas present in the cathode ray tube |
Which of the following conclusions could not be derived from Rutherford's -particle scattering experiment?
| 1. | Most of the space in the atom is empty. |
| 2. | The radius of the atom is about 10-10 m while that of a nucleus is 10–15 m. |
| 3. | Electrons move in circular path of fixed energy called orbits. |
| 4. | Electrons and the nucleus are held together by electrostatic forces of attraction. |
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
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