An unusual lightning strike has a vertical portion with a positive current of +400 A upwards. The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 ?T. In N, the force exerted by the Earth's magnetic field on the 25 m-long current is
a. 0.
b. 0.012 N, East.
c. 0.012 N, West.
d. 0.30 N, West.
e. 300 N, East.
d
You might also like to view...
Hydrogen gas seems to have a diffusivity of about 2.6 x 10^-13 m^2/s when diffusing into iron at 770 K. What would you expect the rate of diffusion or mass flow rate per unit area of hydrogen to be when stored in an iron container at 5 atmospheres pressure, assuming the density of hydrogen at 1 mm in the iron from the containing surface to be 5% of the normal hydrogen density, given by p/RT?
What will be an ideal response?
The period-luminosity relation is useful in determining
a. the mass of a star for which the distance is known. b. the temperature of a star for which we know the luminosity. c. the radius of the bulge of our galaxy. d. the distance to globular clusters that contain Cepheid variables. e. the mass of the Milky Way galaxy.
The principle of continuity states that for fluid flow to be continuous it must
A) speed up in narrow regions of flow. B) slow down in wide regions of flow. C) both of these D) neither of these
In ultrasound the _____________ of the sound is much greater than in normal sound
a. frequency b. period c. wavelength d. amplitude e. speed