Photoelectric Effect and Light Wavelengths

The video tutorial explains the photoelectric effect, focusing on how light of certain frequencies can eject electrons from metal surfaces. It covers the concept of threshold frequency, the effect of light intensity, and how to calculate the kinetic energy and speed of ejected electrons. The tutorial also includes examples with potassium and calcium metals, demonstrating how to convert work functions and calculate maximum wavelengths.

What is the basic principle behind the photoelectric effect?

• Light can make a metal magnetic.

• Light of a certain frequency can eject electrons from a metal surface.

• Light can increase the temperature of a metal.

• Light can change the color of a metal.

Which color of light is generally insufficient to eject electrons from most metals?

• Yellow light

• Red light

• Green light

• Blue light

What happens if the frequency of light is below the threshold frequency?

• Electrons are ejected with less energy.

• No electrons are ejected.

• Electrons are ejected with more energy.

• The metal changes color.

How is the threshold frequency calculated?

• By dividing the work function by the speed of light.

• By adding the work function to Planck's constant.

• By multiplying the work function by Planck's constant.

• By dividing the work function by Planck's constant.

What is the kinetic energy of an electron if the energy of the photon is 300 joules and the work function is 200 joules?

• 300 joules

• 200 joules

• 100 joules

• 500 joules

What is the maximum wavelength of light needed to free an electron from potassium metal?

• 670 nanometers

• 540 nanometers

• 480 nanometers

• 450 nanometers

Which light wavelength is sufficient to eject electrons from potassium metal?

• 670 nanometers

• 540 nanometers

• 480 nanometers

• 700 nanometers

How do you convert the work function from kilojoules per mole to electron volts?

• Divide by 1.6 x 10^-19 and multiply by Avogadro's number.

• Divide by Avogadro's number and multiply by 1.6 x 10^-19.

• Multiply by Avogadro's number and divide by 1.6 x 10^-19.

• Multiply by 1.6 x 10^-19 and divide by Avogadro's number.

What is the work function of calcium metal in electron volts?

• 4.59 eV

• 3.68 eV

• 5.40 eV

• 2.87 eV

What is the maximum wavelength of light needed to free an electron from calcium metal?

• 480 nanometers

• 433 nanometers

• 540 nanometers

• 670 nanometers