1. A proton is moving perpendicular to a magnetic field at 3.0 10⁶ m/s and experiences a magnetic force of magnitude 2.5 10¹⁶ N. What is the magnitude of the magnetic field?

a. 5.2 10⁴ T

b. 2.6 10⁴ T

c. 1.9 10³ T

d. 3.8 10² T

e. 0.52 T

2. An electron is moving at 3.0 10⁶ m/s at an angle of 40 to a 0.80 T magnetic field. What is the magnitude of the force on the electron?

a. 1.2 10¹³ N

b. 2.9 10¹³ N

c. 2.5 10¹³ N

d. 3.8 10¹³ N

e. 4.8 10¹³ N

3. If a 20 W laser beam, which has an initial diameter of 2.0 mm, spreads out to a diameter of 2.0 m after traveling 10,000 m, what is the final intensity of the beam?

a. 6.4 10⁶ W/m²

b. 6.4 W/m²

c. 20 10⁸ W/m²

d. 20 10⁶ W/m²

e. 20 10⁴ W/m²