The source of the earth's magnetic field is thought to be due to the motion of charged particles in the earth's
A) mantle.
B) crust.
C) inner core.
D) outer core.
E) mantle & crust.
D
You might also like to view...
Light of wavelength 575 nm falls on a double-slit and the third order bright fringe is seen at an angle of 6.5°. What is the separation between the double slits?
A) 5.0 ?m B) 10 ?m C) 15 ?m D) 20 ?m E) 25 ?m
The half-life of cobalt-60 is 5.3 years, while that of strontium-90 is about 29 years
Suppose you have samples of both isotopes, and that they initially contain equal numbers of atoms of these isotopes. How will the activities (number of decays per second) of the samples compare? A) The activities will be equal. B) The activity of the cobalt-60 sample will be greater. C) The activity of the strontium-90 sample will be greater. D) The activities cannot be compared without more information.
About 90% of the star's total life is spent on the main sequence
Indicate whether the statement is true or false
What is the major problem with the U.S. customary system?
a. It is out of date. b. Understanding the units does not require knowing English. c. It has many different unfamiliar units and conversions are difficult. d. It avoids cumbersome conversions of units. e. It does not allow conversion to metric units.