Optics SOSI 2016 Matt Chalker

Event Summary Two Sections Test – Various Optics topics (see list in rules) – 50% of final score Hands on “Laser Shoot Activity” – Accurately reflect laser to a target

Laser Shoot Activity Bounce laser off mirrors at target point

Laser Shoot Details Setup – 4 minutes Use of up to 5 mirrors Variable target point on back wall 1 barrier on center line for B 3 barriers (one on center line) in Division C – 1 barrier has an additional mirror on it

Scoring Test Score - (Part I score / Highest Part I score of all teams) x 50 points Accuracy Score - (25 – (accuracy (in mm)/10)) points. The smallest possible AS is 0. Mirror Score - # Mirrors x 4 points (20 max) Barrier Score - 5 points if the laser reflects off the barrier mirror Final Score = TS + AS + MS + BS (100 is max)

Sample Geometric Questions Regionals – A man is walking at 1.0 m/s directly towards a flat mirror. At what speed is his separation from his image decreasing? 2.0 m/s – What kind of lens curvature is used in most magnifying glasses? Convex – What is the index of refraction for water? 1.33

Sample Geometric Questions cont. State – The apex angle of a prism is 60 o and the minimum deviation angle is 20 o. What is the index of refraction of the prism? 1.29 – In a typical prism produced rainbow, which color of visible light is bent the least? Red – A thin converging lens with a focal length of 30 cm produces a virtual image 30 cm away. What is the object distance? 15 cm

Sample Geometric Questions cont. Nationals – Light with a frequency of 7.5 x Hz is traveling through water. What is its wavelength? 3.0 x m – What is diopter of a concave mirror with a focal length of 40cm? 2.5 – If a concave lens has a radius of curvature on one side of 40 cm and 60 cm on the other side, and is made out of a material with an index of refraction of 1.75, what is the focal length? 32 cm

Sample Physical Questions Regionals – What is the term for adding black to a color? Shading – Where do far-sighted peoples’ eyes focus? Behind the retina – The complementary color of green light is? Red – What is the name of the EM region between UV and gamma rays? X-Rays – What is the name for light with a slightly longer wavelength than visible light? Infrared

Sample Physical Questions cont. State – What structure of the eye acts as the aperture? Pupil – What is the approximately frequency of yellow light? ~517 THz – When the light from a star is found to be redshifted, what does that mean about the star’s motion relative to the observer? Moving Away – How many lines are there in the emission spectrum of Hydrogen? 4

Sample Physical Questions cont. Nationals – The intensity of radiation from the Sun is ~1370 W/m 2 on Earth (1 AU from the sun). What is the Sun’s intensity at Mercury (0.387 AU)? 9140 W/m 2 – What is the approximate field of view size of the eye’s blind spot? 7.5 o high 5.5 o wide – If an object known to emit a wavelength of 555 nm is observed to have a Doppler shift of 8 nm, how fast is it moving relative to the observer? 4324 km/s

Selection of Nationals 2011 C Exam questions