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 conclusions could not be derived from Rutherford's $\mathrm{\alpha }$-particle scattering experiment?

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. ${}_8{}^{16}\mathrm{S}$

4. ${}_{16}{}^{32}\mathrm{S}$

Which of the following statement is not correct about the characteristics of cathode rays?

A monochromatic infrared range finder of power 1mW 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. \(5 \times 10^{11} \)

Match the following:

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 x 10^-20 J

2. 2.922 x 10^-19 J

3. 4.031 x 10¹⁹ J

4. 2.319 x 10^-18 J

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 energies E₁ and E₂ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e., ${\mathrm{\lambda }}_1$ and ${\mathrm{\lambda }}_2$ will be:

1.  ${\mathrm{\lambda }}_1=2{\mathrm{\lambda }}_2$

2.  ${\mathrm{\lambda }}_1=4{\mathrm{\lambda }}_2$

3.  ${\mathrm{\lambda }}_1=\frac{1}{2}{\mathrm{\lambda }}_2$

4.  ${\mathrm{\lambda }}_1={\mathrm{\lambda }}_2$