Watch dials contain radium glow because
A. all radioactivity creates light
B. batteries supply energy when a button is pushed
C. the radiation hits a phosphor
D. They don't glow. Only tritium glows.
Answer: C. the radiation hits a phosphor
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Where does the celestial equator intersect the ecliptic?
A. at the zenith B. at the southern horizon C. at the summer solstice D. at the equinoxes
The solution to the solar neutrino problem was
A) the Sun's core is cooling down, producing less neutrinos that expected. B) 2/3 of the neutrinos transform into a new type during the 8-minute trip to Earth. C) the corona is opaque to much of the neutrino radiation. D) the Earth's ozone layer absorbs 2/3 of the neutrinos in transit. E) our solar energy equations were just wrong, and needed much reworking.
Work-Energy Theorem: A 100-N force has a horizontal component of 80 N and a vertical component of 60 N. The force is applied to a cart on a level frictionless floor. The cart starts from rest and moves 2.0 m horizontally along the floor due to this force. What is the cart's final kinetic energy?
A. 200 J B. 160 J C. 120 J D. zero
The erosion features seen from orbit on the surface of Mars appears to have been formed from
A) running water B) molten lava C) wind D) marsquakes