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Question
The half-life of a radioactive isotope is 140 days. In how many days does the decay rate of a sample of this isotope decrease to one fourth its initial decay rate?A) 35 days
B) 70 days
C) 105 days
D) 210 days
E) 280 days
Answer
This answer is hidden. It contains 1 characters.
Related questions
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The intensity of the microwave background radiation, a remnant of the big bang:
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Any meson is a combination of:
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Q:
In a photoelectric effect experiment at a frequency above cut off, the stopping potential is proportional to:
A) the energy of the least energetic electron before it is ejected
B) the energy of the least energetic electron after it is ejected
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D) the energy of the most energetic electron after it is ejected
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Q:
In a photoelectric effect experiment at a frequency above cut off, the number of electrons ejected is proportional to:
A) their kinetic energy
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Q:
The units of the Planck constant hare those of:
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B) 0.22mc2
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A particle with zero mass and energy Ecarries momentum:
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Q:
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Q:
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Q:
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Q:
Figure (i) shows a double-slit pattern obtained using monochromatic light. Consider the following five possible changes in conditions:
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2) increase the frequency
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4) increase the separation between the slits
5) decrease the separation between the slits
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Q:
The resolving power of a telescope can be increased by:
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Q:
Light of wavelength 480 nm falls on a slit of width 3.5 m. What is the relative intensity (that is, the value of I/Im) of the diffraction pattern at an angle of 18?
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Q:
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