Quiz on Light Energy

What did Einstein postulate light is composed of?

• Atoms

• Wave packets

• Molecules

• Particles

What is the formula for the energy of a photon?

• E = QV

• E = 1/2mv^2

• E = mc^2

• E = hf

What is the unit of energy equal to the work done when 1 electron is moved through a p.d. of 1V?

• Ampere

• Electronvolt

• Watt

• Joule

What is the formula for the momentum of a photon?

• p = E / c

• p = QV

• p = mv

• p = hf

What is the threshold frequency for the photoelectric effect?

• Frequency at which emission is maximum

• Frequency above which emission occurs

• Frequency at which absorption occurs

• Frequency below which emission does not occur

What did Louis De Broglie theorize about particles with mass?

• They possess only particle properties

• They are invisible

• They possess wave properties

• They are stationary

What is the wavelength associated with a moving particle according to de Broglie?

• λ = QV

• λ = E / c

• λ = hf

• λ = h / p

What can be used to determine the composition of distant stars?

• Quantum physics

• Emission and absorption line spectra

• Photoelectric effect

• Wave-particle duality