C$.$ Regular problems. Show the steps clearly; answer only is not acceptable!

Start by writing the equation you will be using $($include what you are calculating on the left side of the equal sign$)$ then plug in the explicitly the numbers used in the formula, finally calculate. Include the correct unit for each final answer.

For more details, see instructions on page $2$ of this exam paper.

A concave$-$convex converging lens has radii curvature $R_1=20cm$ and $R_2=10cm$ as shown in the picture on the right. The refractive index of the lens material is $n=1\mathrm{.}5.$

a$.$ Calculate the focal length of the lens!

Concave

Convex

$R_1=20c\frac{m}{R_2}=10cm$

b$.$ An object is placed at $120$ cm in front of the lens. Calculate the location of the image from the lens.

$$

c$.$ Calculate the magnification of the image by the lens.

W$/$rita tha anauinn..................

d$.$ If the height of the object is $6$ cm $,$ calculate the height of the image. Is the image real or virtual? Is the image upright or flipped upside down?

e$.$ On the grid below do the followings: $($i$)$ locate the focal points of the lens and the center points C $.$

$($ii$)$ Then, use a ruler to draw the special rays to locate the image. $($iii$)$ Draw also a ray from the object that allows the person $($shown head only in the picture$)$ to see the image. Your drawing must be precise; the image may not be off from the calculated location by more than half a grid on either side.