Electricity and Magnetism Answers

Find the magnetic field at the point O, if the current is = 100 А and =20 cm.
2. The thin wire carrying the current =10 A is bent into the rectangle with sides 6 cm and =10.5 cm. Find the magnetic field at the point of diagonals intersection.
3. A horizontal wire carries a current of 48 A towards the east. A second wire with mass 0.05 kg runs parallel to the first, but lies 15 cm below it. This second wire is held in suspension by the magnetic field of the first wire above it. If each wire has a length of half a meter, what is the magnitude and direction of the current in the lower wire?
4. An electron having 880 eV of energy moves at right angles to a uniform magnetic field of flux density 2.5·10-3 T. Show that the path of the electron is a circle and find its radius.

find gradient of scalar fields

W = 2p (z^2 + 1) cos Φ

1-2 parallel very long wires 1 and 2 are separated by a distance of 0,065m and carry currents I1 of 15A and I2=7A.What is the magnitude of the force that the magnetic field that wire 1 applies to a 1,5m of wire 2 when the currents are in opposite direction.
2-A 150 turn solenoid carries a current of 12A,the radius of the solenoid is 0,050m and its strength is 0,18m.what is the magnetic flux through the circular crodd-sectional area at the center of the solenoid?

The electrons in the beam of television tube have an energy of 12 keV
( ). The tube is oriented so that the electrons move horizontally from
south to north. At MIT, the Earth's magnetic field points roughly vertically down (i.e.
neglect the component that is directed toward magnetic north) and has magnitude B ~
T.
19 1 eV 1.6 10 J − = ×
5 5 10− ×

. The interstellar space in the Milky Way has magnetic field of about 3 micro G. This space also
has approximately one Hydrogen atom per cm3
, which have thermal velocity of about 103m/s.
Compare the magnetic field energy stored in a volume of interstellar space with the kinetic
energy of thermal motion.

A 60kg hiker climbs up to the top of a hill that is 250m vertically above the starting position. The change is gravitational potential energy is

An ideal transformer steps down a voltage of 240 V to supply power to a lamp with a power rating of 9 V, 0.9 A. If the brightness of the lamp is normal, what is the current flowing in the primary coil? (Show and upload your work solution)

An electrical mini speaker for home requires 9 V to function. The voltage of the electrical supply is 240 V. What is the turns ratio of the transformer that must be used? (Show and upload your work solution)

the work function of silver is 4.73eV EM radiation with a frequency of 1.2x10^15 Hz strikes a piece of pure silver,what is the speed of the electrons that are emitted

A metal disc of radius 1m is rotating in Earth’s gravitational field with its axis parallel to
the field. The field strength is 0.5 G. What should be the rotation velocity for the potential
difference between the center and the circumference of the disc to be 1 mV.?