What Are the Characteristics and Effects of Electromagnetic Forces and Fields?

[nautica]

19) An LC circuit consist of a 1 microFarad capacitor and a 4 mH inductor. Its oscillation frequency is approximately:

21) Electrons are going around a circle in a counterclockwise direction. At the center of the circle they produce a magnetic field that is:

Out of the page.

23) the units of motional emf are

a) volt/second
b) volt meter/second
c) volt/tesla
d) tesla/second
e) tesla meter squared/second

24) two parallel wires, 4 cm apart, carry currents of 2 A and 4 A respectively, in opposite directions. the force per unit length in N/m of one wire on the other is

a) 10^-3 repulsive]
b) 10^-3 attractive
c) 4x10^-5 replusive
d) " attractive
e) none

26 Units of magnetic field might be?

a) C m/s
b) C s/m
c) C/kg
d) kg/C s
e) N/C m

Thanks again
Nautica

 

[himanshu121]

$$f= \frac{1}{\sqrt{LC}}$$

 

[M98Ranger]

19) The oscillation frequency of this LC circuit can be calculated using the formula f = 1/(2π√(LC)). Plugging in the values of C = 1 microFarad and L = 4 mH, we get f = 1/(2π√(1 microFarad x 4 mH)) = 1/(2π√(4 x 10^-9)) = 1/(2π x 2 x 10^-3) = 1/(4π x 10^-3) = 250 Hz. Therefore, the oscillation frequency of this LC circuit is approximately 250 Hz.

21) The magnetic field produced by the electrons going around a circle in a counterclockwise direction will be out of the page. This is because the direction of the magnetic field is perpendicular to the direction of the current flow, and in this case, the current flow is in the counterclockwise direction.

23) The units of motional emf are volt/second. This is because motional emf is the induced voltage in a conductor moving through a magnetic field, and voltage is measured in volts and time is measured in seconds.

24) The force per unit length of one wire on the other can be calculated using the formula F = μ0I1I2/(2πd), where μ0 is the permeability of free space, I1 and I2 are the currents in the two wires, and d is the distance between the wires. Plugging in the values of μ0 = 4π x 10^-7 N/A^2, I1 = 2 A, I2 = 4 A, and d = 4 cm = 0.04 m, we get F = (4π x 10^-7 N/A^2) x (2 A) x (4 A)/(2π x 0.04 m) = 1.6 x 10^-3 N/m. This force per unit length is attractive, as the currents in the two wires are in opposite directions.

26) The units of magnetic field can be expressed as tesla (T), which is equivalent to N/(A x m) or kg/(A x s^2). Therefore, option c) C/kg is the correct answer.