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Question
If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amount?A) 12 hours
B) 24 hours
C) 48 hours
D) 72 hours
E) practically forever, but it may be safe by then
Answer
This answer is hidden. It contains 1 characters.
Related questions
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Heat energy is measured in units of
A) degrees.
B) joules.
C) calories.
D) both joules and calories.
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When the temperature of a fixed volume of air initially at 0 C is lowered by 1 degree, its pressure
A) decreases by 1/273.
B) decreases by 100/273.
C) increases by 1/273.
D) increases by 100/273.
Q:
Which of these is the smallest?
A) 1 Celsius degree
B) 1 kelvin
C) 1 Fahrenheit degree
D) all are the same
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On which temperature scale is 0 degrees the freezing point of water?
A) Celsius
B) Caloric
C) Kelvin
D) Fahrenheit
E) none of the above
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Whether one object is warmer than another object has most to do with molecular
A) kinetic energy.
B) potential energy.
C) masses.
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If water had a lower specific heat capacity, would ponds and lakes be more or less likely to freeze in winter?
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Distinguish between the concepts of thermal energy, temperature, and heat.
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A) surface of bodies of water.
B) layer of water slightly below the surface.
C) bottom of bodies of water.
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Water at 4C will expand when it is slightly
A) cooled.
B) warmed.
C) both of these
D) none of the above
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If water at 0C slightly increases in temperature, the water
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B) expands.
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If water at 20C slightly increases in temperature, the water
A) expands.
B) contracts.
C) remains the same.
Q:
The operation of a bimetallic strip relies on differences in
A) expansions of metals.
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Q:
A kg of 40C water and a kg of 20C water, after being mixed, have a temperature of 30C. However, the final temperature of a 1-kg iron block at 40C placed into 1 kg of water at 20C is
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The moderate temperatures of islands throughout the world has mainly to do with water's
A) poor conductivity.
B) vast supply of thermal energy.
C) high specific heat capacity.
D) high evaporation rate.
E) absorption of solar energy.
Q:
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A) iron
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C) the same
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As entropy in a system increases, energy within the system
A) becomes more ordered.
B) becomes less ordered.
C) reaches equilibrium.
D) moves toward destruction.
Q:
When work is done by a system and heat is subtracted, the temperature of the system
A) increases.
B) decreases.
C) remains unchanged.
Q:
Which law of thermodynamics addresses the direction of heat flow?
A) First law
B) Second law
C) Third law
D) all of the above
Q:
Which law of thermodynamics states that no system can reach absolute zero?
A) First law
B) Second law
C) Third law
D) all of the above
Q:
At some point between Earth and the Moon, the forces due to gravity on a space traveler would be the same when this point is
A) nearer Earth.
B) nearer the Moon.
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Two objects move toward each other due to gravity. As the objects get closer and closer, the acceleration of each
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B) decreases.
C) is not affected.
Q:
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A) less the gravitational force between them.
B) more the gravitational force between them.
C) constancy of the force between them.
Q:
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them doesn't change, then the force between them is
A) one-quarter.
B) half as much.
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D) four times as much.
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If Earth's mass somehow decreased with no change in its radius, your weight would
A) decrease also.
B) increase.
C) remain the same.
Q:
Newton discovered
A) gravity.
B) that gravity is universal.
C) neither of these
Q:
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A) go into circular orbit about Earth.
B) rise and fall back to Earth's surface.
C) follow an uncertain path.
D) escape from Earth.
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An Earth satellite in an elliptical orbit travels slowest when it is
A) nearest the Earth.
B) farthest from the Earth.
C) neither of these
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An Earth satellite in an elliptical orbit travels fastest when it is
A) nearest the Earth.
B) farthest from the Earth.
C) neither of these
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From Earth, one satellite appears to overtake another. The faster satellite that is seen to overtake the other is
A) higher.
B) lower.
C) can't say
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The fastest moving planet in a solar system is the
A) smallest planet.
B) most massive planet.
C) planet nearest the Sun.
D) planet farthest from the Sun.
E) none of the above