Physics 41 Exam 2 Spring 2012

Transcription

1 Physics 4 Exam 2 Sprig 202 Name: Coceptual Questios ad Short P (2 Poits Each) Circle the BEST aswer!. A les produces a sharply-focused, iverted image o a scree as show. What will you see o the scree if the les is removed? a. The image will be as it was, but much dimmer. b. The image will be right-side-up ad sharp. c. The image will be right-side-up ad blurry. d. The image will be iverted ad blurry. e. There will be o image at all. 2. The image show is: a. real b. virtual c. magical 3. The first-order diffractio of moochromatic x rays from crystal A occurs at a agle of 20. The first-order diffractio of the same x rays from crystal B occurs at 30. Which crystal has the larger atomic spacig? a. Crystal A b. Crystal B c. Same d. Impossible to determie 4. White light passes through a diffractio gratig ad forms raibow patters. For each raibow, a. the red side is o the right, the violet side o the left. b. the red side is o the left, the violet side o the right. c. the red side is closest to the ceter of the scree, the violet side is farthest from the ceter. d. the red side is farthest from the ceter of the scree, the violet side is closest to the ceter. 5. Match the light itesity patters with the type of slit diffractio: (a) (b) (c) Sigle Slit Diffractio: Double Slit Diffractio: Diffractio Gratig 6. For a covex les, if the object is located a shorter distace tha the focal legth, the image will be a) real, upright ad larger b) real, iverted ad smaller c) real, upright ad smaller d) virtual, upright ad larger d) virtual, upright ad larger 7. For a cocave mirror, if the object is located a greater distace tha the focal legth, the image will be a) real, upright ad larger b) real, iverted ad smaller c) real, upright ad smaller d) virtual, upright ad larger d) virtual, iverted ad larger 8. Light of wavelegth illumiates a double slit, ad iterferece friges are observed o a scree. Whe the wavelegth is chaged to 2, the friges get further apart. How does the size of 2 compare to? Α) 2 is larger tha. B) 2 is smaller tha. C) Not eough iformatio to aswer. 9. A film of idex of refractio coats a surface with idex of refractio 2. Whe < 2, the coditio for destructive iterferece for reflected moochromatic light of wavelegth i air is a. t = m. b. t = m+. c. 2 2t = m. d. 2t = m+. e. 2 4t = m. 0. White light falls o a soap bubble ad blue wavelegths are destroyed. What color do you see? a.. cya b. mageta c. yellow d. red e. gree f. blue

2 Short Problems (7 poits each) Show your work for ANY credit. Box Aswers. Circle the best aswer.. A diver i the water shies a uderwater searchlight at the surface of a pod ( =.33). At what agle (relative to the ormal) will the light be totally reflected? a. 47 b. 4 c. 5 d. 58 e The large space telescope that has bee placed ito a Earth orbit has a aperture diameter of 2.4 meters. What agular resolutio will this telescope achieve for visible light of wavelegth = m? a rads b rads c rads d rads e rads 3. Moochromatic light from a He-Ne laser ( = m) is icidet o a diffractio gratig cotaiig 5000 lies/cm. Determie the agle of the first-order maximum. a. 8.4 b c. 4.6 d e Light reflected off a plate-glass widow ( =.5) is foud to be completely polarized at agle-of-icidece θ. Fid θ. a b. 5.7 c. 2.2 d. 8.6 e Three polarizig disks whose plaes are parallel are cetered o a commo axis. The directio of the trasmissio axis i each case as show relative to the commo vertical directio. A upolarized beam of light is icidet from the left o the first disk with itesity Ii = 0.0 W/m 2. Calculate the trasmitted itesity If i W/m 2 whe θ = 20.0, θ2 = 40.0, ad θ3 = a b..30 c..47 d e. 6.89

3 Log Problems. (5 pts each) NEATNESS COUNTS! BOX fial umerical aswers!!. A arrow beam of white light eters a equilateral prism made of crow glass at 45.0 degrees icidet agle as show. At what agle does the red (660.0 m) compoet of the light emerge from the prism relative the ormal of the right side? The idex of refractio for red light i crow glass is.52. Redraw the prism large eough to have room to label rays ad agles.

4 2. Coheret light of wavelegth 650.0m is set through two parallel slits ad a iterferece patter i formed o a scree at a distace L=2.50 m behid the slits. Each slit is a = µ m wide. Their ceters are d= 2.80 µ m apart. a) Derive from scratch the equatio for the positio of costructive iterferece friges o the scree above the ceter of the cetral bright frige i terms of the variables L, d,, ad θ. b) Fid the agle to the 3 rd bright frige. c) Fid the itesity of light o the scree at the ceter of the 3 rd bright frige, expressed as a fractio of the light itesity Imax at the ceter of the patter.

5 3. A object, height 2.00 cm, is located 3.00 cm from a divergig les with a focal legth of cm. A. Use the les equatio to fid the locatio, magificatio ad height of the image. B. Draw the situatio to scale to locate the image, idetifyig the three rays. Measure the image locatio ad height ad calculate the magificatio. Compare your result for the image locatio with what you foud i part A. Please label everythig. NEATNESS COUNTS. Box ad label your aswers.