A nichrome wire and an aluminum wire, each with the same initial resistance, have the same change in resistance when heated separately. (rAl = 2.82 × 10^-8 W × m; aAl = 3.9 × 10^-3 / °C; rnichrome = 1.50 × 10^-6 W × m; anichrome = 0.40 × 10^-3 / °C.) The ratio of the temperature change of the nichrome wire to the temperature change of the aluminum wire is
a. 0.019.
b. 0.10.
c. 0.18.
d. 9.8.
e. 53.
D
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A proton moving at 3 × 10^4 m/s is projected at an angle of 30° above a horizontal plane. If an electric field of 400 N/C is directed downwards, how long does it take the proton to return to the horizontal plane? (HINT: Ignore gravity.) [mProton = 1.67 × 10^-27 kg, qProton = +1.6 × 10^-19 C.]
Bragg reflection results in a first-order maximum at 12.2°. In this case, at what angle would the second-order maximum occur?
a. 24.4° b. 12.2° c. 7.79° d. 25.0° e. 78.5°
A right triangle has sides 5 m, 12 m, and 13 m. What is the sine of the smallest angle of this triangle?
1.12/5 2.5/12 3.5/13 4.12/13
Two mirrors are joined together along a common side, the planes of the mirrors separated by the angle q. If the joined mirrors can be used as a retroreflector when a beam of light strikes both surfaces (one after the other), what is the value of q?
a. 90° c. 45° b. 135° d. 30°