Which fundamental physical law states that the magnitude of an induced electromotive force (EMF) in a closed circuit is directly proportional to the rate of change of magnetic flux through it?

According to Lenz's Law, the direction of an induced current will always:

Electrical circuit problem 19: If a direct current of 2 Amperes flows through a resistor when a potential difference of 39 Volts is applied, what is its resistance?

Electrical circuit problem 18: If a direct current of 2 Amperes flows through a resistor when a potential difference of 38 Volts is applied, what is its resistance?

Electrical circuit problem 17: If a direct current of 2 Amperes flows through a resistor when a potential difference of 37 Volts is applied, what is its resistance?

Electrical circuit problem 16: If a direct current of 2 Amperes flows through a resistor when a potential difference of 36 Volts is applied, what is its resistance?

Electrical circuit problem 15: If a direct current of 2 Amperes flows through a resistor when a potential difference of 35 Volts is applied, what is its resistance?