Question 1 :
The separation between two microscopic particles is measured $P_A$ and $P_B$ by two different lights of wavelength $2000\ A^o$ and $3000\ A^o$ respectively, then

Question 2 :
The focal length of a convex lens is $5\,cm$,where should the object be placed to get  a real image with same size as that of object:

Question 3 :
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 4 :
If a lens is cut into two pieces perpendicular to the principal axis and only one part is used, the intensity of the image

Question 5 :
An object is placed on the principal axis of a convex mirror of focal length 15 cm. If the distance of the object from the mirror is 30 cm, determine the image distance

Question 6 :
The nature of image formed when an object is placed near to a concave lens is _____

Question 7 :
The magnifying power of a simple microscope can be increased if we use eye piece of :

Question 8 :
The magnifying power of a simple microscope can be increased if we use an eyepiece of

Question 9 :
Lens A produces a magnification of -0.8 whereas lens B produces a magnification of +0.8. Which one of the following applies to lenses A and B?

Question 11 :
A water film is formed on a glass-block. A light ray is incident on water film from air at an angle of$\displaystyle { 60 }^{ \circ }$ with the normal. The angle of incidence on glass slab is<br>($\displaystyle { \mu }_{ g } = 1.5,{ \mu }_{ w } = \frac { 4 }{ 3 }$)

Question 12 :
A piano-convex lens (refractive index $\mu_1$) fits exactly into a piano-concave lens (refractive index $\mu_2$). Their plane surfaces are parallel to each other. R is the radius of curvature of the curved surface of the lenses, then focal length of the combination is:<br/>

Question 13 :
A solid transparent sphere has a small opaque dot at its centre. When observed from outside, the apparent position of the dot will be

Question 14 :
A thin convex lens made of glass of&#160; $\mu =$ 1.5 has refracting surfaces of radii of curvature 10 cm each. The left space of lens contains air and the right space is filled with water of refractive index $\dfrac{4}{3}$. A parallel beam of light is incident on it. The position of the image is :<br/>

Question 15 :
An object and a screen are mounted on an optical bench and a converging lens is placed between them so that a sharp image is received on the screen. The linear magnification of the image is $2.5$. The lens is now moved $30\ cm$ nearer the screen and a sharp image is again formed on the screen. The focal length of the lens is: