Physics

• Which objects give out their own light

  Luminous objects
• What objects do not produce their own light

  Non-luminous objects
• What are the 3 things that could happen when light reaches an object.  It could be reflected, transmitted or absorbed
• What type of object transmits most of the light.

  Transparent objects
• What type of objects transmit some of the light

  Translucent objects
• What type of object transmits non of the light

  Opaque objects
• How does light travel?

  In a straight line in a particular direction
• How do we represent light on a diagram?

  A thin straight line (drawn with a ruler) with an arrow.
• How do we see luminous objects?

  When the light coming from that object enters our eyes
• How do we see a non- luminous object?

  When they reflect light into our eyes
• How fast does light travel?

  300 million m/s
• What happens when the light travels further?

  It gets less intense
• What is the calculation for speed?

  Distance/time
• What is the calculation for time?

  Distance/speed
• What is a light year?

  How far light can travel in one year- it is a distance not a time!
• What happens when light hits an opaque object?

  It creates a region where light is blocked called a shadow
• What is a point source?

  Where all light rays appear to come from one exact point. E.g a Lazer
• What is the area where no light reaches called?

  An umbra
• What is the area where some light reaches called?

  Penumbra
• What happens to the shadow as the point source gets further away?

  The shadow gets smaller
• What happens to the shadow when the objects gets closer to the light source?

  The shadow gets smaller
• Where does the shadow form?

  The screen
• What happens to your shadow as the sun get higher in the sky

  It gets shorter
• What is an extended source?

  A light source with a wide surface and where light rays come from the whole of the surface.
• How many light rays do you draw on a diagram with a point source?

  2 lines
• How many light rays do you draw on a diagram with an extended source?

  4 light rays
• What are the shadows like with a pint source?

  Sharp shadows
• What are the shadows like with an extended source?

  Shadow with blurred edges.
• How many shadows are there with a point source?

  1 shadow- umbra
• How many shadows are there with an extended source?

  3 shadows- 1 umbra and 2 penumbra's
• What does eclipse mean?

  To block the light from one object because another object passed Infront of it.
• What happens to an object that has been eclipsed?

  That object can no longer be seen
• What are the two types of eclipse?

  Luna and solar
• What is a solar eclipse?

  Where light from the sun is blocked by the moon (can't see the sun)
• What is a lunar eclipse?

  Where light reflected from the moon in blocked by the Earth (can't see the moon)
• Why are we more likely to see a lunar eclipses than solar eclipses?

  Either because lunar eclipse last longer thn solar eclipses or the earth casts larger shadows than the moon.
• Wha tis a satellite?

  Any object that orbits a more massive object
• How often does the moon orbit the Earth?

  Every 27.3 days which is roughly equal to once a month.
• What are all the moon phases in order?

  New, waxing Cresent, first quarter, waxing gibbous, full, waning gibbous, third quarter, waning Cresent.
• What is the image like that your see on the screen of a pinhole camera?

  Sharp, bright and inverted