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

Answer:

15.7 x 10⁻⁶ A

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

$i = - A\left ( \frac{\Delta B}{\Delta t} \right )$

$i = \left ( \frac{A}{R} \right )\left ( \frac{\Delta B}{\Delta t} \right )$

$i = \left ( \frac{-0.002826}{18} \right )\left ( \frac{- 0.10}{1} \right )$

i = 15.7 x 10⁻⁶ A