Light Energy

Question 1

What are the two main sources of light?

Answer 1

The two main sources of light are natural sources, like the sun, and artificial sources, such as light bulbs.

Question 2

What is the difference between luminous and non-luminous objects?

Answer 2

Luminous objects emit their own light (e.g., the sun, a candle), while non-luminous objects do not emit light but can reflect light from luminous sources (e.g., the moon, a chair).

Question 3

How are speed, frequency, and wavelength of light related?

Answer 3

The speed of light (𝑐) is the product of its frequency (𝑓) and wavelength (𝜆):
𝑐 = 𝑓 × 𝜆
Light travels at approximately
3 × 10^8 meters per second in a vacuum.

Question 4

How are shadows and eclipses formed?

Answer 4

Shadows form when an opaque object blocks light, creating a dark area behind it.

An eclipse occurs when one celestial body moves into the shadow of another; a solar eclipse happens when the moon blocks the sun’s light, and a lunar eclipse occurs when the earth’s shadow falls on the moon.

Question 5

Q: How does a pin-hole camera work?
A: A pin-hole camera works by allowing light from an object to pass through a small hole and project an inverted image on the opposite side inside the camera. The size of the hole and distance between the hole and the screen affect the image’s clarity and brightness.