A lamp beam on a curved panel

In the picture

1. 1The small bright circle on the panel: light arriving straight on, packed into a small area
2. 2The wide pale band on the panel: the same light arriving at a slant, spread over a larger area
3. 3The glowing bulb of the lamp: the source that sends out the beam

Examples

• The midday sun feels hotter than the sun in the late afternoon.
• A torch held straight at your hand makes a small hot circle, but tilted it makes a bigger, weaker patch.

Quiz: A lamp beam on a curved panel (Age 11)

1. 1

   When light lands straight on a surface, what happens to its energy?

   • It is packed into a small area, so that spot gets warmer.
   • It disappears before it can warm the surface.
   • It is spread over a wide area, so each part gets less warmth.
2. 2

   When the same light lands at a slant, what happens to its energy?

   • It is spread over a wider area, so each part gets less warmth.
   • It changes into a different kind of energy.
   • It is packed into a tiny spot, so that spot gets warmer.
3. 3

   Why does slanted light warm each part of a surface less than straight-on light does?

   • The surface blocks slanted light completely.
   • The same energy is spread over a larger area.
   • The light loses all its energy when it slants.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.