# A proton is moving with a velocity v = (3 x 105 i + 7 x 105 k) m/sec in a region where there is a magnetic field B = 0.4j T. Find the force experienced by the proton.

solution

velocity of proton=(3 x 105 i + 7 x 105 k) m\s

magnetic field B = 0.4j T.

we know that mass of proton (mp)=1.67  x 10-27

charge of proton(q)=1.6 x 10-19c

force experienced by the proton= ?

we have a relation

$$\vec{f}$$=q($$\vec{v}*\vec{B}$$)

=1.6 x 10-19 (3 x 105$$\hat{i}$$  + 7 x 105$$\hat{k}$$) x 0.4$$\hat{j}$$

=1.6 x 1o-19(1.2 x 105 $$\hat{k}$$ -2.8 x 105$$\hat{j}$$)

=1.6 x 10-19 (1.2 $$\hat{k}$$ – 2.8$$\hat{j}$$) x 105

=(1.92 $$\hat{k}$$ – 4.48$$\hat{j}$$ x 10-14 N