The distance between the optical centre and the principal focus of a lens is known as
Optical centre
Principal focus
Focal length
None of these
When we stand in sunlight we feel the heat due to the presence of
Infrared radiation
Ultraviolet radiation
Radio waves
Electromagnetic radiation
The defect of hypermetropia may be corrected by using
Concave lens
Convex lens
Prism
Which of the following joins the centres of curvatures of the two spherical surface of the lens?
Centre of curvature
Radius of curvature
Principal axis
Name the scientist who is often considered as father of modern physics
Sir.Isaac Newton
Albert Einstein
Christian Huygens
Willebrord Snell
Where will the image be formed when the object is at infinity ?
At F
At F on other side of the lens
At 2F
At 2F on other side of the lens
Hypermetropia which develops at an advanced age in life is known as
Myopia
Presbyopia
Cataract
The point at which the incident ray meets the separating surface is called
Point of incidence
Point of refraction
Point of diversion
A medium is said to be optically dense if the speed of light become
Faster
Slower
Not changed
The separation of a beam of white light into its constituent colours is known as
Refraction of light
Reflection of light
Dispersion of light
