Radio waves, Microwaves, Infrared rays, Visible light rays (ROYGBIV), Ultraviolet rays, X-rays, Gamma rays.
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Category: FAQs
List the properties of electromagnetic waves.
- They transfer energy from a wave source
- They are transverse waves
- They travel with the same speed of 3×108 m/s in vacuum
- They can travel through vacuum. No medium required for its transmission.
- They travel in straight lines.
Define focal length.
Focal length is the distance between the optical centre and the focal point.
State the two conditions needed for total internal reflection to occur.
- The light ray is travelling from a denser optical medium to a less dense optical medium.
- The angle of incidence in the denser medium is greater than the critical angle of the medium.
Define total internal reflection.
Total internal reflection occurs when the angle of incidence in the optically denser medium is greater than the critical angle, causing the light ray to be reflected in the denser medium, and no light ray being refracted.
Define critical angle.
Critical angle is the angle of incidence in the optically denser medium for which the angle of refraction in the less dense medium is 90o.
State the Laws of refraction.
First Law of Refraction:
The incident ray, the normal and the refracted ray all lie in the same plane.
Second Law of Refraction:
The ratio of sine of the angle of incidence to the sine of the angle of refraction is a constant.
(sin i / sin r = constant)
Define Refraction of light.
Refraction of light is the bending of light as it passes from one optical medium into another optical medium of different densities.
What are the characteristics of a plane mirror image?
- Same size as object
- Laterally inverted
- Upright
- Virtual (it cannot be captured on a screen)
- Distance of image from mirror is same as distance of object from mirror
Define Reflection of light
Reflection of light is the bouncing of light rays off a medium.