Electricity and Magnetism Answers

Near the equator, the earth's magnetic field points almost horizontally to the north and has magnitude B = 0.5 x 10 ^-4 T. What should be the magnitude and direction for the velocity of an electron if its weight is exactly balanced by the magnetic pole? 

A trumpet creates a sound intensity level of 112 dB at a distance of 2.75 m. (a) What is the sound intensity of a trumpet at this distance. (b) What is the sound intensity of seven trumpets played simultaneously at this distance? (c) Calculate the sound intensity level of the seven trumpets played simultaneously at this distance.

What is the force of repulsion between two small charges 75.0 cm apart if each has a charge of 1.65 x 10 -12 C? 

1. How far from a convex lens of focal length 25.0 cm must an object be placed to produced an image that is upright and magnified twice?
2. What is the resulting focal length and power if two thin lenses of focal length

+ 25cm and -50 cm are in contact?

The magnitude of the self-induced electromotive force in solenoid is 0.02 V when the current is increasing at a rate of 0.054 A/s

(a) Find the inductance of the solenoid

(b) If the solenoid has 350 turns, what is the magnetic flux through each turn when the current is 0.63 A?

A proton moving horizontally at 3.5 x 10^4m/s enters a uniform magnetic field of 0.075 T directed upward 30° with the horizontal. Find the magnitude of the magnetic force acting on the proton.

Assume that you want to hold two spherical objects together with an electrostatic force having magnitude of 2.0 × 10^6 N, and they are separated by 1.0 m. If each sphere holds equal charge, how much should each have?

A particle of charge 3 x 10-9 C is located at point (0,0) in a certain coordinate system. Assuming all lengths are in meters, calculate the potential at the following points: A(3,4) and B(0,2). How much work is needed to take a particle of charge 2 x 10-5 C from point A to point B?

The damage threshold for the retina is 100 W/m^2. This means that a damage to the retina can occur at an average intensity greater than this. The light coming from a 5.0 mW green laser has a diameter of 1.2 mm. (a) Will this laser exceed the damage threshold for the retina? (b) What are the maximum values of the electric and magnetic fields of the beam coming from this laser?

Find the measurement of the angle of refraction