Question

1. What prevents rainbows from being seen as complete circles?
2. How much unpolarized light does an ideal Polaroid filter transmit?
3. The source of all electromagnetic radiation is ____,
4. Which of the following has the shortest wavelengths: ultraviolet or infrared?
15. Which requires a physical medium to travel through: light, sound, or both?

Answer 1

A-1. Rainbows are actually full circles. We only see an arc or semicircle because we are standing on the ground and therefore the other half of the rainbow is cut off by the horizon. Hence, ground interferes, which prevent rainbows from being seen as complete circles.

A-2. When unpolarized light is passed through Polaroid filter, it emerges with one half of the intensity as Polaroid blocks one of the two planes of vibration of light. Therefore Polaroid filter makes unpolarized light polarized. Hence it transmits half of the unpolarized light.

A-3. Electromagnetic radiation is produced by the acceleration of the charged particles mainly due to the electric field.

A-4. Ultraviolet has a shorter wavelength as it has much higher frequency and energy than infrared.

A-15. Sound requires a Physical medium to travel. Light does not require a physical medium to travel as it can travel in a vacuum as well.