Q.1.
If a wave's speed is 5m/s and it has a wavelength of 2.5m, what is it's frequency?
Q.2.
Twinkling of stars is due to
Q.3.
A real image is formed by a a convex lens, then it is put in contact with a concave lens and again a real image is formed. This image is : ______________
Q.4.
Magnification of lens can be represented as M = .......
Q.5.
A mirror used as surveillance mirrors in groceries and parking spaces
Q.6.
For total internal reflection to take place ray of light should go from
Q.7.
Which colour of light travels fastest in any medium except air ?
Q.8.
A boy uses blue colour of light to find the refractive index of glass. He then repeats the experiment using red colour of light.How will the refractive index of glass be ?
Q.9.
As the ray of light passes from air to glass, state how the wavelength of light changes.
Q.10.
A monochromatic beam of light of wavelength λ passes from air into a glass block. choose the correct relation.
Q.11.
How is scattering of light proportional to wavelength
Q.12.
The speed of light in glass is 2 ×km/s. What is the refractive index of glass?
Q.13.
Name the factors that affect the lateral displacement of light as it passes through a rectangular glass slab.
Q.14.
A plano convex lens (f = 20cm) is silvered at plane surface. Now f will be
Q.15.
A ray of light is incident on a glass sphere of refractive index 1.5 . What should be the angle of incidence so that the ray which enters the sphere does not come out of the sphere?
Q.16.
Focal length of a convex lens will be maximum for
Q.17.
A double convex thin lens made of glass (refractive index  = 1.has both radii of curvature of magnitudecm. Incident light rays parallel to the axis of the lens will converge at a distance L such that
Q.18.
If the distances of an object and its virtual image from the focus of a convex lens of focal length f are 1 cm each, then f is _______________
Q.19.
The angle of incidence for an equilateral prism isWhat should be the refractive index of prism so that the ray is parallel to the base inside the prism?
Q.20.
An object is held 9cm from a convex mirror and produces an image 6cm tall that is 4cm away from the mirror. What is the height of the object?