WAEC Past Questions and Answers - Page 2833

Refraction occurs when light travels from one medium to another which changes the speed at which the light travels.

This causes light to bend upon incidence with the interface of a new material.

 Angle of refraction is smaller than angle of incidence when light ray travels from rarer medium to denser medium.

I.e  light can either refract towards the normal(when slowing down while crossing the boundary) or away from the normal (when speeding up while crossing the boundary).

When light undergoes refraction, its frequency remains the same.

No explanation has been provided for this answer.

Radiation is energy that comes from a source and travels through space and may be able to penetrate various materials.

Light, radio, and microwaves are good examples

L1=50.
T1 = 30 + 273 = 303k
Linear expansivity =  1.9 x 10\(^{-5}\)

L2 = 50.29

Temp rise= ?

L2 - L1 = 50.29 - 50 = 0.29
Linear expansivity = \(\frac{L2-L1}{L1(T2-T1)}\)

1.9 x 10\(^{-5}\) = \(\frac{0.29}{50*(T2 - 303)}\)

1.9 x 10\(^{-5}\) * 50 (T2 - 303) = 0.29

T2 = \(\frac{0.29}{50 * 1.9 * 10^{-5}}\) + 303

T2 = 152.6 °C

All electromagnetic waves are:

• transverse waves; can travel through a vacuum ;
• travel at exactly the same speed in a vacuum, the speed of light, 300,000,000 m/s.
• transfer energy from one place to another;
• can be reflected;
• can be refracted .
• The oscillations of and are perpendicular to each other and are in the same phase.