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 :

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

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. \(5 \times 10^{11} \)

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 × 10^–20 J

2. 2.922 × 10^–19 J

3. 4.031 × 10¹⁹ J

4. 2.319 × 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.  ${\mathrm{\lambda }}_1={\mathrm{\lambda }}_2$