Question 2 :
Which of the below is one of the laws of refraction?<br>

Question 3 :
The focal length of a concave lens is $2m$. Then the power of the lens is:<br/>

Question 5 :
Choose the correct answer:<br>The nature of image formed by convex mirror is:

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

Question 7 :
The angle between reflected and refracted beams is $90^0$in the water air interface. The angle of incidence in water is

Question 8 :
The focal length of the objective of a telescope&#160;is $60$ cm. To obtain a magnification of $20$ for the&#160;relaxed eye, the length of telescope should be

Question 9 :
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 11 :
The diameter of the reflecting surface of spherical mirror is called ..............

Question 12 :
Image of an object at infinity is formed by a convex lens of focal length $30 \ cm$ such that the size of the image is $2 \ cm$. If a concave lens of focal length $20\&#160; cm$ is placed in between the convex lens and the image, at a distance $26\&#160; cm$ from the convex lens, size of the new image is:

Question 13 :
Air has refractive index $1.0003$. Find the thickness of air column which will contain one more wavelength of yellow light of $6000$ $A^0$ than in same thickness of vacuum.