periscope

• what is a periscope


  periscope is an object that can be used to see over a wall
• what is refraction


  the bending of light
• what is reflection


  change in direction of a wavefront, causing it to bouce back
• what happens to light when it enters from one medium (one state to another)

  it changes direction
• what angle is it when the light comes out from a source

  it is the angle of incidence