A 30 cm long solenoid with a cross sectional radius of 0.75…

A 30 cm long solenoid with a cross sectional radius of 0.75 cm has 125 turns of wire.  The solenoid is connected in series to a switch, a 9 V battery, and a 10 Ω resistor.  The switch is initially open and then is closed.  What is the rate of change in current when the potential difference across the resistor is 3 V?

A square loop of wire of side 0.5 meter and resistance 0.01…

A square loop of wire of side 0.5 meter and resistance 0.01 Ω is located in a uniform magnetic field of intensity 0.4 T directed out of the page as shown below. The magnitude of the field is decreased to zero at a constant rate in 2 seconds. As the field is decreased, what are the magnitude and direction of the current in the loop?