2003 AAPT PHYSICS OLYMPIAD - comPADRE

25. An electromagnetic wave is moving to the right. At oneinstant at point P, the electric field vector E is pointing towardsthe top of the page. In which direction would the magnetic fieldvector B point at this moment?A) to the rightB) to the leftC) into the paperD) out of the paperE) towards the bottom of the paper26. An object is placed 60 cm from a convex converging lens. The image produced isinverted and half the size of the object. What would be focal length of the lens?A) 90 cm B) 60 cm C) 45 cm D) 30 cm E) 20 cm27. A transmission diffraction grating is ruled with 5000 lines per cm. Through what anglewill the first order maxima be deflected when light with a wavelength of 4.5 x 10 -7 m strikes thegrating at an angle of incidence of 0 o .A) 5.2 o B) 6.4 o C) 13 o D) 27 o E) 34 o28. Non-polarized light first passes through one polarizing filter and then through a second.If the intensity of light emerging from the second filter is 12.5 % of the light that struck the firstfilter, at what angle must the axes of the two filters be with respect to one another?A) 7 o B) 30 o C) 42 o D) 60 0 E) 83 o29. Assume that sodium produces monochromatic light with a wavelength of 5.89 x 10 -7 m.At what rate would a 10 watt sodium vapor light be emitting photons?A) 3.5 x 10 19 photons/s D) 2.0 x 10 19 photons/sB) 3.0 x 10 19 photons/s E) 1.5 x 10 19 photons/sC) 2.5 x 10 19 photons/s30. One object has twice the temperature of a second identical object. How does the rate R 1at which the first object radiates energy compare to the rate R 2 at which the second objectradiates energy?A) R 1 = R 2 B) R 1 = 2R 2 C) R 1 = 4R 2 D) R 1 = 8R 2 E) R 1 = 16R 22003 Physics Olympiad 7