consider an electron near the equator. in which direction does it tend to deflect by the magnetic field of the earth if its velocity is directed
a. downward
b.northward
c.westward
d.woutheastward
You are asking four different questions. The Earth's magnetic field near the equator will be in a south-to-north direction, more or less. (See
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In each case, the "q V" vector of the electron will be opposite to the direction of V. To get the direction of the force, which is the direction of the deflection, determine the vector cross product (qV) x B
For (a), qV is up and B is north; so, using the right hand rule, the electron deflection is west.
To determine the direction in which an electron near the equator deflects due to the magnetic field of the Earth, we need to consider the interaction between the velocity of the electron and the magnetic field.
The direction of the magnetic force experienced by a moving charged particle is given by the right-hand rule. If you imagine taking your right hand, with your thumb pointing in the direction of the electron's velocity, and your fingers pointing in the direction of the magnetic field, the palm of your hand will indicate the direction of the magnetic force.
Since the velocity of the electron is directed downward (Option a), we can take our right hand and point our thumb downward. Now, we need to determine the direction of the magnetic field near the equator.
The Earth's magnetic field lines run from the geographic south pole to the geographic north pole and are tilted at an angle with respect to the Earth's surface. At the equator, the magnetic field is roughly horizontal, pointing from geographic west to east. So, we can point our fingers in the westward direction.
Now, if we place our right hand with the thumb downward and the fingers pointing westward, the palm of our hand will indicate the direction of deflection. In this case, the palm would be pointing in the southeastward direction.
Therefore, the electron near the equator would tend to deflect in the southeastward direction (Option d) due to the Earth's magnetic field if its velocity is directed downward.