Magnetic field from electron motion in two directions

[yayirunin2car]

Homework Statement

An electron moving with a speed of 9.0 multiplied by 105 m/s in the positive y direction experiences zero magnetic force. When it moves in the positive z direction it experiences a force of 1.7 multiplied by 10-13 N that points in the negative x direction. What is the magnitude and direction of the magnetic field?

Homework Equations

B = F/(|q|vsinθ)

The Attempt at a Solution

I plugged in the force, the velocity, the charge as 1.60e-19, and guessed that the angle was 90 degrees between the velocity and magnetic field vectors. My answer was wrong, and my guess of the direction of the magnetic field in the positive y direction was also wrong. So, I'm hoping it's in the negative y direction.

Any help?

Thanks in advance!

 

[TSny]

I plugged in the force, the velocity, the charge as 1.60e-19, and guessed that the angle was 90 degrees between the velocity and magnetic field vectors. My answer was wrong, and my guess of the direction of the magnetic field in the positive y direction was also wrong. So, I'm hoping it's in the negative y direction.

Details of the calculation are not shown. So, it is difficult to identify the mistake. Be sure to take into account the sign of the charge of the electron.