Question 1 :
Two thin lenses of power $+3.5D, -2D$ are placed in contact. Find the power of lens combination.

Question 2 :
A symmetric double convex lens is cut in two equal parts by a plane containing the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be

Question 3 :
Aconvex lens of radii of curvature 20 cm and 30 cm respectively. It is silveredat the surface which has smaller radius of curvature. Then it will behave as $(\mu_g\, = \, 1.5)$

Question 4 :
When a light of wavelength $4000$ $\displaystyle \overset { \circ  }{ A } $ in vacuum travels through the same thickness in diamond and water separately, the difference in the number of waves is $200$. Find the thickness, if refractive indices of diamond and water are $\displaystyle \frac { 5 }{ 2 } $ and $\displaystyle \frac { 4 }{ 3 } $ respectively.

Question 5 :
In the table below, column I lists various mirrors &#160;and lenses and column II their uses, qualities or properties.<br/><table class="wysiwyg-table"><tbody><tr><td>column &#160;I</td><td>Column II</td></tr><tr><td>I. Plane mirror</td><td>A. Feels thinner in the middle.</td></tr><tr><td>II. Concave mirror</td><td>B. Always forms virtual image.</td></tr><tr><td>III. Convex mirror</td><td>C. Always forms virtual image of smaller size.</td></tr><tr><td>IV. Concave lens&#160;</td><td>D.&#160;Is used by dentists to examine teeth.</td></tr><tr><td>V. Convex lens</td><td>E. Can be used as reading glass.<br/></td></tr></tbody></table>The correct matching is:

Question 6 :
What happens when a ray of light is made to fall on a mirror along the normal?<br/>

Question 7 :
The distance between an object and its doubly magnified image by a concave mirror is: [ Assume $f$ = focal length]

Question 8 :
Let the x-z plane be the boundary between two transparent media. Medium $1$ in $z\ge 0$ has a refractive index of $\sqrt { 2 } $ and medium $2$ with $z&lt; 0$ has refractive index of $\sqrt { 3 } $. A ray of light in medium $1$ given by the vector $\vec { A } =6\sqrt { 3 } \hat { i } +8\sqrt { 3 } \hat { j } -10\hat { k } $ is incident on the plane of separation. The angle of refraction in medium $2$ is:

Question 9 :
The diameter of the reflecting surface of spherical mirror is called ..............

Question 10 :
A short linear object of length $b$ lies along the axis of a concave mirror of focal length $f$ at a distance u from the pole of the mirror. The size of the image is approximately equal to :<br>