reflection & refraction

• what do we use for this practical?

  a ray box, a lens and a slit
• what does the apparatus produce?

  a narrow ray of light
• what do we do first?

  take a piece of A3 paper and draw a straight line down the centre using a ruler, we then use a protractor to draw a line at right angels, this is the normal (label this N)
• where do we place a place block and why?

  against the first line, so that the normal is near the centre of the block
• what do we draw around?

  the glass block
• what do we do to the room?

  turn off all the lights
• what do we do with the ray box once we are prepared?

  we use the box to direct a ray of light so it hits the block at the normal, this is the incident ray
• what is the angle of incidence?

  the angle between the incident ray and the normal
• why do we adjust the ray box?

  to change the angle of incidence
• what do we see at a certain angle?

  a ray reflect from the surface of the block. we also see another ray leaving the block from the opposite side. this is the transmitted ray.
• what do we mark?

  the path of the incidence ray and the reflected ray with crosses. we also mark the path of the transmitted ray.
• what do we draw onto the paper after completing the experiment?

  the incident ray, the reflected ray and the transmitted ray. we also draw a line to show the path of the transmitted ray through the glass block.
• what angles do we need to measure?

  the angle of incidence and the angle of reflection. we then measure the angle of refraction.
• what is the angle of refraction?

  the angle between the normal and the transmitted ray through the block
• what do we do after completing the experiment?

  do it again, this time using a block made from a different material