What causes the ""heat island"" effect? a. heat produced from a large number of people b. the materials used in building cities retain heat c. the large amount of reflected light from glass windows d. all of the above

3. a particle with initial velocity v⃗ 0=(5.85×103m/s)j^ enters a region of uniform electric and magnetic fields. the magnetic field in the region is b⃗ =−(1.35t)k^. you can ignore the weight of the particle. a. calculate the magnitude of the electric field in the region if the particle is to pass through undeflected, for a particle of charge +0.640 nc.