Artificially induced radioactive elements generally have
A) long half-lives.
B) short half-lives.
C) no half-lives.
Answer: B
You might also like to view...
What is the primary topic of study in quantum mechanics?
A) subatomic particles and the forces with which they interact B) the role played by atoms in astronomy C) the mechanical movements of the heavens D) the role of relativity in astronomy
What is bought from an electric company?
a. Electrical energy b. Electric charge c. Electrical power d. None of these
A copper sphere initially at a uniform temperature of 132°C is suddenly released at the bottom of a large bath of bismuth at 500°C. The sphere diameter is 1 cm and it rises through the bath at 1 m/s. How far will the sphere rise before its center temperature is 300°C? What is its surface temperature at that point? (The sphere has a thin nickel plating to protect the copper from the bismuth.)
GIVEN
• A copper sphere with a thin nickel plating rising through a bath of bismuth
• Initial copper temperature (To) = 132°C (uniform)
• Bismuth temperature (T?) = 500°C
• Ascent velocity (U?) = 1 m/s
• Sphere diameter (D) = 1 cm = 0.01 m
FIND
(a) Distance sphere will rise before its center temperature, T(o,t) = 300°C (b) The sphere surface temperature at that time, T(ro,t) ASSUMPTIONS
• Thermal resistance of the nickel plating is negligible
• Thermal properties of the copper can be considered uniform and constant
SKETCH
If a neutron star attains a mass over ________ solar masses it becomes a black hole
Fill in the blank(s) with correct word