Question

A circular loop with a 0.03-m radius and 18-Ω resistance is facing away from this page. A magnetic field that points into the page was 0.35 T one second ago and is now 0.25 T. What current (in which sense of circulation) appears in this loop, if any?

Answer 1

15.7 x 10⁻⁶ A

Step-by-step explanation:

r = radius of the circular loop = 0.03 m

Area of the loop is given as

A = πr² = (3.14) (0.03)² = 0.002826 m²

R = Resistance of the resistor = 189 Ω

ΔB = Change in magnetic field = 0.25 - 0.35 = - 0.10 T

Δt = time interval = 1 sec

Current is given as

`i = - A\left ( (\Delta B)/(\Delta t) \right )`

`i = \left ( (A)/(R) \right )\left ( (\Delta B)/(\Delta t) \right )`

`i = \left ( (-0.002826)/(18) \right )\left ( (- 0.10)/(1) \right )`

i = 15.7 x 10⁻⁶ A