Why do bridges have expansion joints?
a. They would buckle and crack otherwise.
b. to let water run off
c. to absorb vibrations due to traffic
d. for ease in construction
A
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Starting from rest, an electron accelerates through a potential difference of 67 V. What is its de Broglie wavelength? (h = 6.63 × 10^-34 J×s, me = 9.11 × 10^-31 kg, and 1 eV = 1.60 × 10^-19 J)
a. 1.1 × 10^-10 m c. 1.9 × 10^-10 m b. 1.5 × 10^-10 m d. 2.3 × 10^-10 m
It is found that a laser bounced off a glass surface is perfectly polarized when the angle of incidence of the laser beam is 57 degrees from the vertical. What is the angle of the transmitted beam in the case of this material?
A. 
B. 
C. 
D. 
What is the primary reason that astronomers suspect that some jovian moons were captured into their current orbits?
A) Some moons have orbits that are backward (compared to their planet's rotation) or highly inclined to their planet's equator. B) Some moons have a composition that differs from the composition of the planets. C) Astronomers have observed moons being captured. D) Some moons are surprisingly large in size.
Compared to the density of water, our Earth averages about
A) the same density, similar to Saturn. B) 3 times denser, much like our Moon. C) 4 times denser, similar to Mars. D) 5 times denser, like the Mercury and Venus. E) 10 times denser, due to our core of iron and nickel.