Answer:
a) 1.62*10^{-18}N
b) 2.84*10^{-19}N
c) 1.16*10^{-18}N
Step-by-step explanation:
The net force is given by the expression:

By the right hand rule, we know that the direction of the magnetic force is
j X -i = k

Hence, the direction of the magnetic force is the +z direction.
(a) E=4.19V/m k
![F=(1.6*10^(-19)C)[4.19(V)/(m)+(2540(m)/(s))(2.35*10^(-3)T)]=1.62*10^(-18)N](https://img.qammunity.org/2021/formulas/physics/college/iwc5hdh8ihumim32nohshpp024t4lluleg.png)
where we have used q=9.1*10^{-31}kg.
(b) E=-4.19V/m k
![F=(1.6*10^(-19)C)[-4.19(V)/(m)+(2540(m)/(s))(2.35*10^(-3)T)]=2.84*10^(-19)N](https://img.qammunity.org/2021/formulas/physics/college/bn208p92h3z0cjhfip879pam3sqcgu09lk.png)
(c) E=4.19V/m i
In this case the net force will have two components:
![F=(1.6*10^(-19)C)[4.19(V)/(m)\hat{i}+(2540(m)/(s))(2.35*10^(-3)T)\hat{k}]\\\\F=[6.704*10^(-19)\hat{i}+9.55*10^(-19)\hat{k}]N](https://img.qammunity.org/2021/formulas/physics/college/zfc7xprn89y4jead4cno5813u9th4lhqix.png)
and its magnitude will be:

hope this helps!!