Question

A flexible circular loop 0.10 m in diameter lies in a magnetic field of 1.80 T, directed into the plane of the diagram. The loop is pulled at the points indicated by the arrows, forming a loop of zero area in 0.20 s. Find the induced emf in the circuit. What is the direction of the current through R (up or down)? 16b. A rectangular conducting loop 0.25 m on a side lies in a magnetic field directed into the plane of the diagram. During a 2 sec interval of time, the field decreases at a rate of 1.25 T/s and induces a current which generates light from the lightbulb. Find the induced current if the lightbulb's resistance is 5 Ohm. In what direction does the current flow around in circuit of figure? How much energy is dissipated by the bulb during the 2 sec interval?

Answer 1

16a.

a) Induced emf = -NB( $\Delta$ A/ $\Delta$ t) = -1*1.8(0- $\pi$ *0.05²)/0.2 = 0.07 V

b)Field is into page => current is up