At a certain location, the horizontal component of the earth's magnetic field is 2.7 × 10-5 T, due north. A proton moves eastward with just the right speed, so the magnetic force on it balances its weight. Find the speed of the proton.

Therefore the velocity of the proton is m/s towards east.

Explanation:

The mass of proton is m= kg.

q= C is  the magnitude of the charge of a proton.

The earth's magnetic field is B= T toward north.

Let v be the velocity of the proton towards east.

The angle between the velocity of proton towards east and magnetic field towards north is .

We know that,

Now putting the all values

    m/s

Therefore the velocity of the proton is m/s towards east.