optics lesson(1-4)

Question 1

What are luminous objects?

Answer 1

Objects that can produce their own light

Examples include the Sun and light bulbs.

Question 2

What are non-luminous objects?

Answer 2

Objects that only reflect light

Examples include humans and the Moon.

Question 3

What phenomenon occurs when an object gets hotter and eventually produces light?

Answer 3

Incandescence

Examples include molten metal and burning candles.

Question 4

What is the order of colors produced by an incandescent object as it gets hotter?

Answer 4

Red, orange, yellow, white, bluish-white

This sequence reflects increasing temperature.

Question 5

What percentage of electricity is converted into visible light in incandescent bulbs?

Answer 5

5% to 10%

This low efficiency is why incandescent bulbs get very hot.

Question 6

What is a key characteristic of Light-Emitting Diodes (LEDs)?

Answer 6

They are more energy efficient than incandescent bulbs

LEDs are used in applications like Christmas lights and traffic signals.

Question 7

What two processes does a fluorescent light utilize?

Answer 7

Electric discharge and fluorescence

Fluorescent lights contain mercury that emits ultraviolet light.

Question 8

What is the role of the inner surface of a fluorescent light tube?

Answer 8

It is coated with a fluorescent material

This coating converts ultraviolet light into visible light.

Question 9

What is phosphorescence?

Answer 9

The process by which objects ‘glow-in-the-dark’

Phosphors release light over time from seconds to hours.

Question 10

What is chemiluminescence?

Answer 10

The production of light as a direct by-product of a chemical reaction

An example includes glow sticks.

Question 11

What is bioluminescence?

Answer 11

Light produced by living organisms

Examples include certain bacteria, fungi, and marine animals.