Answer:
![B=4.5* 10^(-4)\ T](https://img.qammunity.org/2020/formulas/physics/college/nnro205vutodnb2sflha5vti5aptek88qh.png)
The direction should be in the positive x direction.
Step-by-step explanation:
Given that
Electric filed E= 410 V/m (In Negative y direction)
V= 9.1 x 10 ⁵ m/s
As we know that
F= E q + q.V x B
Given that protons is moving constant speed so ,F=0
F= E q +q. V x B
0= E + V x B
E = -V x B
- 410 j = - ( 9.1 x 10 ⁵ k x B i)
![B=(410)/(9.1* 10^5)\ T](https://img.qammunity.org/2020/formulas/physics/college/n9ghjnk6ikesdqwkzr25zlsf4uidl7ezj6.png)
![B=4.5* 10^(-4)\ T](https://img.qammunity.org/2020/formulas/physics/college/nnro205vutodnb2sflha5vti5aptek88qh.png)
The direction should be in the positive x direction.