Question Text
Question 1 :
A ray of light travelling in air is incident on the plane of a transparent medium. The angle of incident is $45^0$ and that of refraction is $30^0$. The refractive index of the medium with respect to air is:
Question 2 :
The sun appears red at the time of sun-rise and sun-set. This is because:
Question 3 :
In order to increase the angular magnification of a simple microscope, one should increase
Question 4 :
Rainbow is formed in which direction with respect to the sun?
Question 7 :
Scientists identify the elements that are burning in the stars by using which of the following devices?
Question 8 :
When a ray of light traveling in a (A) Medium, is incident at the surface of a (B) Medium such that angle if incidence is (C) than the critical angle for the pair of media, the ray is totally reflected back into the (D) medium. This phenomenon is called total internal reflection.
Question 9 :
A convex lens is used to form real image of an object on a screen. It is observed that even when the positions of the object and that screen are fixed are two position of the lens to form real images. If the heights of the images are $4\ cm$ and $9\ cm$ respectively the height of the object is
Question 10 :
A convex lens is used to form an image of an object on a screen. If the upper half of the lens is covered so that it becomes opaque. Then :
Question 13 :
The magnification produced by the objective lens and the eye of a compound microscope are $25$ and $6$ respectively. The magnifying power of this microscope is
Question 14 :
A thin convex lens of focal length $'f'$ made of crown glass is immersed in a liquid of refractive index $\mu_{1} (\mu_{1} > \mu_{2})$ where $\mu_{c}$ is the refractive index of the crown glass. The convex lens now is
Question 15 :
The focal length of a combination of lenses formed with lenses having powers of $+2.50\ D$ and $-3.75\ D$ will be