Assertion : Small glass beads fixed on traffic signals glow brightly when light falls upon them.
Reason : Light is totally reflected when the angle of incidence exceeds a certain critical value and light travelling in a denser medium is reflected from a rarer medium.
Both A and R are true and R is the correct explanation of A
Both A and R are true but R is not a correct explanation of A
A is true but R is false
A is false but R is true
Which colour is used in signal lamps?
blue
red
orange
yellow
We can see the sun before the actual sunrise by about:
5 minutes
2 minutes
2 hours
20 hours
Total internal reflection can take place when light travels from:
diamond to glass
water to glass
air to water
air to glass
Pick out the longest wavelength from the following types of radiations.
Blue light
Gamma rays
X-rays
Red light
The complementary colour of green is
magenta
purple
cyan
The three primary or basic colours are
red, blue, yellow
yellow, green, orange
red, green, yellow
red, green, blue
The blue colour of sky is due to
scattering of light
refraction of light
diffraction of light
dispersion of light
Rainbows are formed by
reflection and diffraction
refraction and scattering
dispersion and total internal reflection
interference only
Who discovered by his experiments with glass prisms that white light consists of seven colours?
Newton
Brewster
Maxwell
Thomas young
