light

• What is the aim of the investigation described?

  To investigate reflection and refraction of light
• What happens to light when it travels from one material to another?

  It refracts
• How does the refractive index affect light refraction?

  The greater the index, the more it refracts
• What relationship will you investigate in this practical?

  The relationship between angle of incidence and angle of refraction
• How will you calculate the refractive index of the glass block?

  Using measurements of angles of incidence and refraction
• What is the independent variable in this investigation?

  Angle of incidence
• What is the dependent variable in this investigation?

  Angle of refraction
• What are the control variables in this investigation?

  Glass block and light source
• Why is it important to control variables in this investigation?

  To ensure accurate and reliable results
• Who is demonstrating the practical on refraction?

  1. Reese
• What is the first equipment needed for the refraction practical?

  A ray box
• Why is a slit used in the ray box?

  To create a straight ray of light
• What type of block is primarily used in the practical?

  A rectangular glass or perspex block
• What is the purpose of a semicircular block in the experiment?

  It helps explain total internal reflection
• What is the angle of incidence?

  The angle between the ray and the normal
• How is the normal line defined in this experiment?

  It is at 90 degrees to the surface
• What happens to light when it enters a new medium?

  It changes direction and speed
• What is the relationship between the angle of incidence and angle of reflection?

  They are always equal
• What does the angle of refraction indicate?

  How much light bends when entering a medium
• What is the formula to calculate the refractive index?

  $n =$$\frac{\sin I}{\sin R}$
• If the angle of incidence is $45^\circ$ and the angle of refraction is $30^\circ$, what is the refractive index?


  $1.4$
• What does a higher refractive index indicate about light's speed?

  Light travels slower in that medium
• How many angles of incidence and refraction should be measured?

  Five angles
• What is total internal reflection (TIR)?

  Light reflects entirely within a medium
• What is the critical angle?

  The angle of incidence for TIR to occur
• What conditions are necessary for TIR to happen?

  Angle must exceed critical angle in a denser medium
• How does the semicircular block demonstrate TIR differently than the rectangular block?

  It shows TIR only when light exits into air
• What happens to the angle of refraction as the angle of incidence increases towards TIR?

  It approaches 90 degrees
• Why is it important to draw the normal line accurately?

  It ensures correct angle measurements
• What should you do if you want to compare refractive indices of different materials?

  Repeat the experiment with each material
• What are the steps to conduct the refraction practical?

  1. Set up the ray box and slit.
  2. Place the block on paper and trace it.
  3. Draw the normal line at the entry point.
  4. Measure angles of incidence and refraction.
  5. Calculate the refractive index.
  6. Repeat for multiple angles.
  7. Analyze results and plot a graph.
• What are the key concepts related to total internal reflection?

  • Occurs when angle of incidence exceeds critical angle
  • Requires light to be in a denser medium
  • Results in complete reflection with no refraction