Question

A circular conducting loop of radius 17.0 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 235 12. The magnetic field is now increased at a constant rate by a factor of 2.90 in 25.0s. Calculate the magnitude of the induced emf in the loop while the magnetic field is increasing. Submit Answer Tries 0/20 Calculate the magnitude of the current induced in the loop while the field is increasing. Submit Answer With the magnetic field held constant at its new value of 0.87 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 5.30 s. Submit Answer Tries 0/20

Tried this once and got all wrong answers, really unsure about how to solve. please help. will rate.

Answer 1

(a) Area of coil,A = $\pi$r² = 3.14*(0.17)² = 0.09074 m^{​​​​​​2}​​​​​m2

Magnitude of emf = (B_{​​​​​​2} - B_{​​​​​​1}​​​)A/t , here we use, flux = BA and change in flux = change in field*Area = (B2 - B1)A

Where, B_{​​​​​​1} = 0.3 T, B_{​​​​​​2} = (2.9*0.3) T

So, B2 - B1 = 0.3*(2.9 - 1) = 0.57 T

Therefore, emf = (0.57*0.09074/25) = 2.06*10^-3 volt

(b) Magnitude of current = emf/resistance

= (2.06*10^-3/235) = 8.76*10^-6 A

(c) This time the magnetic field will change from 0.87 T to zero when it is pulled out of the magnetic field in time 5.30 seconds.

So, as before, induced voltage is given as

V = Change in field*Area/Time = [(0.87-0)*0.09074/5.30]

= 1.48*10^-2 volt