Which of the following is a secondary colour
blue
orange
red
green
Correct answer is B
Primary colours are red, blue and green
∴ orange is a secondary colour
The ability of the human eye to focus object on the retina is referred to as the power of?
interference
diffraction
accomodation
superposition
Correct answer is C
Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the eye varies.
x is same as in y
x and y is same as in vacuum
x is higher than in y
y is higher than in x
Correct answer is D
Since 1.51, the refractive index of X is greater than 1.33, the refractive index of y, the speed of light in y is higher than that in X
If the refractive index of crown glass is 1.51, its critical angle is?
48.6°
22.5°
41.5°
45.5°
Correct answer is C
Sin c = (1)/n
= (1)/1.51 = 0.6622
∴ c = sin-\(^1\) 0.6622 = 41.47
4. 0 cm
3. 0 cm
12. 0 cm
9. 0 cm
Correct answer is C
f = -12 cm, v = - 6 cm
(1)/v + (1)/u =(1)/f
(1)/-6 + (1)/u = (1)/-12
(1)/u = (1)/-12 + (1)/6 = (1 + 2)/12 = (1)/12
∴ u = 12 cm