# Homework Help: Magnetic force (B)

1. Feb 22, 2010

### jrollz316

an electron m=9.11x10^-31 kg and q= -1.602x10^-19 C enters a region where th magnetic field is constant and perpendicular to the velocity of the electron. the speed of the electron is v=5x10&m/s. the electron moves in a circle of radius 2cm.

a. what is the magnitude B of the magnetic field?
b. what is the periods of the circular motion of the electron? what is the frequency of the motion?
c. the electron radiates as its moves in a circle and emits radiation. what i s the wavelength of this radiation and characterize this radiation? the frequency of the radiation is the same as the frequency of the circular motion of the electron

i would attempt the solution if i knew how to find B. I honestly dont know what to do with this.

2. Feb 22, 2010

### collinsmark

Hello jrollz316,

Welcome to Physics Forums.

Could you give us any equations that might be relevant? Also, let us know what work you have attempted and where you are getting stuck. We're not supposed to help unless you've shown that you've made a solid attempt. Things which may be useful in your reply: What sort of force would cause an object (with mass) to move in a circle? What is the equation for this? Do you know of any equations which relate force F, magnetic field B, and velocity v?