Electricity and Magnetism Answers

the mass of a typical car is m= 1000 kg, so its weight on earths surface is mg=9800N. suppose you have two containers, one with N electrons and another with N protons. these two containers are placed a distance 10m apart, and the electric force between them is equal to the weight of the car. Find N

A flexible rectangular coil of wire with 150 loops is stretched in such a way that its dimension changes from 5 cm x 8 cm to 7 cm x 11 cm in 0.15 s in a magnetic field of 25T that is 30 degrees relative to the plane of the coil.

a. Calculate the induced EMF

b. How much energy in joules was dissipated in the circuit if the total resistance is 100Ω?

A circular antenna of an area 3m2 is installed at a place in NAIA. The plane of an area of antenna is inclined at 47% with the direction of the Earth’s magnetic field. If the magnitude of the earth’s flux linked with the antenna (1nT= 1 x 10-9 T).

A circular loop of wire of radius 0.25 cm is expected to an external magnetic field that is perpendicular to the plane of the loop. For a time, the magnetic field decreases at a rate of 0.0035 T/s. What is the magnitude of the induced electromagnetic force in the loop? 

A flexible rectangular coil of wire with 150 loops is stretched in such a way that its dimension changes from 5 cm x 8 cm to 7 cm x 11 cm in 0.15 s in a magnetic field of 25T that is 30 degrees relative to the plane of the coil.

a. Calculate the induced EMF

b. How much energy in joules was dissipated in the circuit if the total resistance is 100Ω?

Determine the magnitude of the Poynting vector and the energy per unit time delivered to a wire of length L and cross-section A when electric current I flows in it. 

In a cyclotron, the diameter of the pole faces is 100 cm and the magnetic field between the pole faces is 0.50 T. The cyclotron is used for accelerating protons. Calculate the kinetic energy of proton in eV and speed of the proton as it emerges from the cyclotron. Also determine the cyclotron frequency. 

A fuse is made of material that melts when the current density reaches 400 A cm2 . What is the diameter of the fuse wire needed to limit the current to 0.40 A? 

A light hits a surface at an angle of 16°. The material on the other side of the surface has an index of refraction of 1.44 and the light is making an angle of 15° with the surface when it exits on this side. What is the index of refraction on the incident side of the interface?

Light travels through a medium with an index of refraction of 1.04. It comes to the surface of another medium at an angle of 83°. If the index of refraction for this medium is 2.11, what angle does the refracted light make with respect to the surface?