3 Light Intensity: Inverse Square Law

The TIME it takes light from the Sun to reaches us is: Distance = 93,000,000 miles           'c' = 186,000 mi / sec

  $v\ =\ \frac{d}{t}$  

• 2 minutes and 8 seconds (128 seconds) 

• 4 minutes and 10 seconds (250 seconds) 

• 8 minutes and 20 seconds (500 seconds)

• 10 minutes and 20 seconds (620 seconds)

Tags

NGSS.HS-ESS1-1

Why does light refract when it travels through a medium with a different refractive index?

• It changes its speed entering the new medium

• It is reflected away from the material

• Light gets absorbed

• Light is absorbed and reflected leading to refraction

Tags

NGSS.HS-PS4-1

Light traveling through WHICH of the following will travel the SLOWEST? 

'c' in substance = 'c' in vacuum / refractive index 

• Vacuum (of space)

• Air

• Diamond

• Glass

Tags

NGSS.HS-PS4-1

Light Intensity: As one gets further from a light source, the intensity of light....

• Increases

• Decreases

• Gets brighter

• Gets more luminous

Tags

NGSS.HS-PS4-3

As one approaches (gets closer) to a light bulb, the brightness of the bulb....

• Increases (brighter)

• Decreases

• Stays the same

• Changes in some unknown way

Earth's Sun is 93 million miles from Earth. Mercury is closest and Neptune is the furthest planet. Which one experiences the greatest intensity of light energy?

(*of the 3 given)

• Mercury

• Earth

• Neptune

• All 3 receive the same sunlight intensity (it's the Sun)

A student stands 10 feet away from a light bulb. The student walks toward the light bulb to a 5 feet distance. Which is true? Intensity = 1 / d²

• The bulb appears 2x's brighter

• The bulb appears 4x's brighter

• The bulb appears 5x's brighter

• The bulb appears 25x's brighter

At a distance of 1m, the intensity of light is spread over a 1m x 1m area. What is the area of light spread out at distance 2m?

• 1 m²

• 2 m²

• 4 m²

• 8 m²

Based on the picture...what is the RATE of change of light intensity as one moves FURTHER from the light source?

• Light intensity INCREASES at an inverse square

• Light intensity INCREASES as a direct relationship

• Light intensity DECREASES at an inverse square

• Light intensity INCREASES as a direct relationship

SOLVE: A light bulb has an intensity of 50 watts at a distance of 1 meter. What is the intensity of the light at 5 meters? Intensity = 1 / d²

• 1 watt

• 2 watts

• 5 watts

• 10 watts