A 30-year-old woman takes a trip on a rocket, leaving her 20-year-old brother behind. She travels at a speed of 0.8c, and is gone 20 years, according to the younger brother. When she returns, how many years older/younger is she than her brother?
a. 2 years younger
b. 2 years older
c. 3 years older
d. 10 years older
e. 8 years older
b
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Diffraction Gratings: Monochromatic light of wavelength 500 nm is incident normally on a diffraction grating. If the third-order maximum of the diffraction pattern is observed at 32° from the centerline, what is the distance between the slits of the grating?
A. 0.93 ?m B. 1.4 ?m C. 2.8 ?m D. 8.5 ?m
A double convex lens has faces of radii 18.0 cm and 20.0 cm. When an object is placed 24.0 cm from the lens, a real image is formed 32.0 cm from the lens. Determine:
(a) the focal length of the lens. (b) the index of refraction of the lens material.
A 900-kg car traveling east at 15.0 m/s suddenly collides with a 750-kg car traveling north at 20.0 m/s. The cars stick together after the collision. In what direction does the wreckage move just after the collision?
A) 36.9° N of E B) 42.0° N of E C) 45.0° N of E D) 53.1° N of E E) 48.0° N of E
An x-ray photon with wavelength 15.0 pm is scattered at 
by an electron. What is the wavelength of the scattered photon?
A. 31.0 pm B. 14.9 pm C. 1.57 pm D. 17.2 pm E. 12.8 pm