Quiz on Photoelectric Effect Experiments

What did Hertz observe when he shone UV light on a metal surface?

• The metal became negatively charged

• Sparks were produced more easily

• The metal surface got hotter

• The light had no effect on the metal surface

What did Hallwachs’ experiment show about the effect of UV light on metals?

• UV light makes metals lose protons

• UV light can knock electrons out of metals

• UV light can increase the temperature of metals

• UV light has no effect on metals

In Lenard’s experiment, what factor determined the energy of the ejected electrons?

• The metal’s temperature

• The brightness of the light

• The color (wavelength) of the light

• The size of the metal plate

Which type of light was most effective in knocking out electrons in Hallwachs' experiment?

• Visible light

• Infrared light

• UV light

• Red light

What did Lenard discover about the brightness of light in relation to the photoelectric effect?

• Bright light increased the energy of each electron

• Bright light had no effect on the number of electrons

• Bright light increased the number of electrons ejected, but not their energy

• Bright light prevented the ejection of electrons

Hertz’s experiment showed that UV light could help produce sparks in metals. This was an early sign of which effect?

• Compton effect

• Photoelectric effect

• Doppler effect

• Tyndall effect

What happens to the metal surface in Hallwachs’ experiment when it loses electrons?

• It becomes neutral

• It becomes positively charged

• It becomes negatively charged

• It stays the same

Which scientist’s experiment demonstrated that only certain wavelengths of light could knock out electrons from metals?

• Heinrich Hertz

• Wilhelm Hallwachs

• Albert Einstein

• Philipp Lenard

What did Lenard observe when he used light of different colors on a metal surface?

• Only red light could knock out electrons

• Higher energy (shorter wavelength) light ejected electrons with more energy

• Lower energy (longer wavelength) light ejected electrons with more energy

• Color of light had no impact on electron energy

What was the key discovery from these experiments that led to the concept of the photon?

• Light behaves only like a wave

• Electrons have fixed energy in metals

• Light has particle-like properties and can eject electrons if it has enough energy

• Electrons in metals cannot be ejected by light