photoelectric effect2

The only way to increase the number of photoelectrons emitted is by increasing the _________ of the light

• Intensity

• Wavelength

• Frequency

• Energy

The energy of photoelectrons emitted from a metal surface can be increased by

• using light of higher frequency.

• using light of longer wavelength.

• using light of higher intensity.

• using monochromatic, polarized light.

The photoelectric effect only occurs if the light shining on the metal is:

• coherent.
• above a minimum intensity.
• above a minimum frequency.
• above a minimum wavelength.

Does high-frequency or low frequency light cause the ejection of a greater number of electrons from a metal surface?

• only high frequency
• only low frequency
• both of them
• doesn't depend to frequency

What is the best description of 'threshold (critical) frequency'?

• The minimum energy needed for electrons to escape a surface.

• The maximum kinetic energy that an emitted electron has.

• The minimum frequency of a photon that will cause an electron to be emitted.

• The frequency that an emitted electron will have.

To release an electron the energy of the photon had to be more than

• zero

• the critical frequency

• the work function

• the critical wavelength

The energy of the emitted electron is ------------

• hf

• h/f

• hf + Ew

• hf - Ew

The equation for the photoelectric effect is  KE = hf - Ew

The graph of electron energy against frequency is

• a straight line through the origin

•  a straight line slope h

• a straight line with a positive y intercept

• not a straight line

The critical frequency is 

• the highest frequency that releases electrons

• always in the red part of the spectrum

• always in the purple part of the spectrum

• different for different metals

A surface has a work function of 4 x 10⁻¹⁹ J What is the critical wavelength? h = 6.6 x 10⁻³⁴ Js c = 3 x 10⁸ ms⁻¹

• 6.0 x 10⁻¹⁴ m

• 700nm

• 5 x 10⁻⁷ m

• 3 x 10⁻⁶ m