# Inducing Voltage and Current ?

**help me with C (i answered a and b )

a) A circular conducting loop of radius 21.0 cm is located in a region of homogeneous magnetic field of magnitude 0.300 T pointing perpendicular to the plane of the loop. The loop is connected in series with a resistor of 155 Ω. The magnetic field is now increased at a constant rate by a factor of 2.50 in 19.0s.

Calculate the magnitude of the induced emf in the loop while the magnetic field is increasing. answer:3.28×10-3 V.

b)Calculate the magnitude of the current induced in the loop while the field is increasing. answer:2.12×10-5 A

c)With the magnetic field held constant at its new value of 0.75 T, calculate the magnitude of the average induced voltage in the loop while it is pulled horizontally out of the magnetic field region during a time interval of 3.50 s.

Relevance
• (a) Given: A = πr^2 = 3.14 x (0.21)^2 = 0.1385 m^2 & ∆B = {2.5 x 0.300 - 0.300} = 0.45 T & ∆t = 19

=>∆ф = A x ∆B = (0.1385 x 0.45) = 0.0623

By EMF = -N∆ф/∆t {-ve just indicating it is resistive & ф = BA}

=>EMF = 0.0623/19 {as N = 1}

=>EMF = 3.28 x 10^-3 V

(b) By V = iR

=>i = V/R = (3.28 x 10^-3)/155 = 2.12 x 10^-5 A

(c)  Given:  ∆B = {0.75 - 0.45} = 0.30 T & ∆t = 3.5

=>∆ф = A x ∆B = (0.1385 x 0.30) = 0.04155

By EMF = -N∆ф/∆t {-ve just indicating it is resistive & ф = BA}

=>EMF = 0.04155/3.5 {as N = 1}

=>EMF = 1.19 x 10^-2 V

• Login to reply the answers