The design of modern X-ray telescopes depends on
A) lenses made of germanium.
B) the prime focus design, with mirrors made of iron.
C) grazing incidence optics.
D) achromatic lenses to keep the X-rays in focus.
E) the Cassegrain design, with mirrors made of lead.
C
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As you go higher and higher above the surface of the Earth, the mass of a body stays constant
a. True b. False Indicate whether the statement is true or false
Terminal Voltage and Internal Resistance: A battery has an emf ? = 12 V and an internal resistance r = 2.0 ?, as shown in the figure. When a 3.0-? cable is connected across the battery terminals a and b, the rate at which chemical energy in the battery is depleted is closest to
A. 24 W. B. 27 W. C. 29 W. D. 32 W. E. 34 W.
Who won the Nobel Prize for explaining the photoelectric effect?
a. Bohr b. Planck c. de Broglie d. Einstein
Exhibit 13-1
Two blocks of masses m1 and m2 are connected by a light cord that passes over a pulley of mass M, as shown. Block m2 slides on a frictionless horizontal surface. The blocks and pulley are initially at rest. When m1 is released, the blocks accelerate and the pulley rotates.
?
?
Use this exhibit to answer the following question(s).
Refer to . The total angular momentum of the system of the two blocks and the pulley relative to the axis of rotation of the pulley is
a.
proportional to the radius of the pulley.
b.
proportional to the speed of the blocks.
c.
proportional to the length of the string.
d.
to all of the above.
e.
only to (a) and (b) above.