Questions on Electrons and Experiments

What is the effect of applying only electric field on the path of electrons in the cathode ray tube experiment?

• The electrons are deflected towards the positive plate.

• The electrons are deflected towards the negative plate.

• The electrons move in a straight line.

• The electrons stop moving.

Thomson determined the value of e/m_e by:

• Using the oil drop experiment

• Using the cathode ray tube experiment

• Using the gold foil experiment

• Using the Rutherford scattering experiment

The oil drop experiment devised by R.A. Millikan was used to determine:

• The mass of the electron

• The charge on the electron

• The speed of light

• The gravitational constant

How was the mass of the electron determined by combining the results of Millikan's and Thomson's experiments?

• By measuring the charge-to-mass ratio and the charge of the electron

• By measuring the speed and the charge of the electron

• By measuring the mass and the speed of the electron

• By measuring the charge-to-mass ratio and the speed of the electron

Calculate the number of protons, neutrons and electrons in ( ^{80}_{35}Br ).

• Protons: 35, Neutrons: 45, Electrons: 35

• Protons: 35, Neutrons: 80, Electrons: 35

• Protons: 45, Neutrons: 35, Electrons: 45

• Protons: 80, Neutrons: 35, Electrons: 80

The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. Assign the proper symbol to the species.

• S

• O

• S^2-

• O^2-

What is the visible light region in the electromagnetic spectrum?

• 400-700 nm

• 700-1000 nm

• 100-400 nm

• 1000-1500 nm

What is the relationship between frequency, wavelength, and velocity of light?

• Velocity = Frequency x Wavelength

• Frequency = Velocity x Wavelength

• Wavelength = Velocity x Frequency

• Velocity = Wavelength / Frequency

Explain the concept of quantisation as described in the text.

When electromagnetic radiation of wavelength 300 nm falls on the surface of sodium, electrons are emitted with a kinetic energy of 1.68 x 10^-19 J mol^-1. What is the minimum energy needed to remove an electron from sodium? What is the maximum wavelength that will cause a photoelectron to be emitted?

• 2.14 x 10^-19 J, 580 nm

• 1.68 x 10^-19 J, 300 nm

• 3.00 x 10^-19 J, 400 nm

• 1.00 x 10^-19 J, 700 nm