Question

Q1: Answer the following questions 1 For a concave lens, if the focal point is set at 55 mm while the object is set at 130mm find the image location and the magnification factor. Describe the image. 2- The image of the concave lens is always virtual and larger than the object. [True or False] Justify. For a lens with focal length f- 70mm, in general at: A- Which object-image positions are most like that of a magnifying glass? 3- Interpret the meaning of the following lens parameters values: a s'-44 mm b- m- 0,9 c- f--32mm Q2: Answer the following questions 1. If you set the Polaroid orientations transmitted light? to i-47° and -185°, Calculate the intensity of the 2. Find the light intensity after the first Polaroid, if Pi-70° Suggest two values for I and 3. to have zero light intensity. A 633 nm laser light is passed through a narrow slit and a diffraction pattern is observed on a screen L-6.0 m away. The distance on the screen between the centers of the first minima outside the central bright fringe is 32 mm. What is the slit width a ? 4. sine- 22/a sin0-2/a sin0- 0 0 sine--2/a -)1 sine -22/a -2 IL Viewing screen 6 m

Answer 1

1) By Lens Formula

$\frac{1}{v}- \frac{1}{u} = \frac{1}{f}$

f = - 55 mm

u = - 130 mm

So,

+ f 55 130 u

38.65mm

i.e. Image is at 38.65 mm left of the lens.

Magnification m = v/u = -38.65 / -130 = + 0.297

Positive sign indicates image is erect.

Also it is an virtual image.

Standard Sign Convention for thin lens are used here.