When a beam of light enters one medium from another, which quantity will not change?

• Direction

• Speed

• Frequency

• Wavelength

Dispersion is used to describe the

• Splitting of white light into its component colors

• Propagation of light in straight lines

• Bending of a beam of light when it goes from one medium to another

• Bending of a beam light when it strikes a mirror

The wavelength of light has no role in

• Diffraction

• Interference

• Polarization

• Reflection

Laser light is ______ emission.

• Coherent

• Stimulated

• Spontaneous

• Coherent and stimulated

Which of the following factor does not harm laser efficiency?

• Atmospheric absorption

• Excitation energy not absorbed

• Problems in depopulating the lower laser level

• Inefficiency in populating the upper laser level

Monochromatic means that ?

• the light consist of two colors
• the light consist of only one color
• the light consist of three color
• only two light wavelengths are distinguished

Laser stands for ?

• light amplification by the stimulated emission of radiation.
• electromagnetic radiation to which the organs of sight react

which is an application of laser?

• medical application 
• Communication 
• cutting metals
• all of the above 

The picture indicates which property ? 

• Laser is Monochromatic 
• Laser is Coherent
• Laser is Directional 

One quantum of light energy is called a .........