Q.1
Can the image formed by the simple microscope be projected on screen without using any
additional lens or mirror?
Q.2
Why are mirrors used in search lights parabolic and not spherical?
Q.3
A convex lens forms the image of the sun at a distance of 20cm. where will the image be
formed when another lens of same aperture but different power is used?
Q.4
Magnifying power of simple microscope is inversely proportional to the focal length of lens.
What stops us from using convex lens of smaller and smaller focal length and achieving
greater and greater magnifying power?
Q.5
Under what conditions do total internal reflection takes place? Calculate the speed of light in
a medium whose critical angle is 450
[Marks 5 x 2]
Q.6
Show that convex lens produces N times magnified image when the object distances from the
lens have magnitudes f 
f
N
. Here f is the magnitude of the focal length of the lens. Hence
find two values of object distance for which convex lens of power 2.5D will produce an image
that is four times as large as the object?
Q.7
Draw a ray diagram to show how an image is formed when object is placed between f and 2f
of a thin concave lens. Deduce the relation between the object distance, the image distance
and the focal length of lens under this condition.
Q.8
Draw a ray diagram to show the formation of image of a point object placed in a medium of
refractive index n1 on the principal axis of a convex spherical surface of radius of curvature R
and refractive index n2. Using the diagram derive the relation
n 2 n1 n 2  n1


v
u
R
where u and v
have their usual meanings
[Marks 3x3]
Q.9
Draw a labeled diagram of compound microscope, showing the formation of image at least
distance of distinct vision. [b] A compound microscope uses an objective lens of focal length
4cm and eye lens of focal length 10cm. An object is placed at 6cm from the objective lens.
Calculate the magnifying power of the compound microscope if final image is at near point.
Also calculate the length of the microscope.
[5]