Light and optics

What is the range of wavelengths for visible light?

• 100 nm to 400 nm

• 380 nm to 700 nm

• 700 nm to 1000 nm

• 300 nm to 500 nm
  

What is the main difference between luminous and illuminated objects?

• Luminous objects reflect light; illuminated objects produce it.

• Luminous objects glow only under UV light

• Luminous objects produce their own light; illuminated objects reflect light

• Illuminated objects can only be seen in the dark

3. Which type of light production is used in glow sticks and some living organisms?

• Incandescence

• Phosphorescence

• Chemiluminescence

• Fluorescence

Why can’t we see through opaque materials?

• They reflect all light

• They allow only UV light to pass

• They block visible light completely

• They scatter all light

How do TVs and screens produce all visible colors?

• By using a wide range of dyes

• By projecting white light through color filters

• By mixing red, green, and blue light in different intensities

• By using brown, cyan, and yellow as primary colors

What are the primary subtractive colors?

• Red, green, blue

• Cyan, magenta, yellow

• Red, yellow, blue

• Green, magenta, orange

What happens when pigments are mixed?

• They reflect more colors

• They become transparent

• They reflect fewer colors

• They emit light

What does the law of reflection state?

• Light always reflects straight back
  

• The angle of incidence is random

• Angle of incidence = angle of reflection

• Reflected light bends

Why is a mirror image considered virtual?

• It’s upside down

• Rays don’t meet behind the mirror

• It’s larger than the object

• It can be projected

What is the main difference between real and virtual images?

• Virtual images are always smaller

• Real images are brighter

• Real = rays meet; virtual = don’t

• Virtual images only form in darkness