There is a circuit with 2 resistors in series and a cell of 3.0v. what is the resistance across the first resistor if the current through it is 0.2a and pd across 2.0v also whats the pd for second circuit?

The resistance of the  first resistor is, R₁ = 10 Ω

Explanation:

Given data,

The potential of the cell v = 3 V

The current through the first resistor, I = 0.2 A

The P.D across the first resistor, v₁ = 2.0 V

Let R₁, and R₂ be the resistance of the resistors,

Since the voltage across the series connection is,

                                   v = v₁ + v₂

Substituting the values

                                    3 V = 2 V + v₂

∴                                       v₂ = 1 V

Hence, the P.D across the second resistor is, v₂ = 1 V

The resistance of the first resistor is,

                                   R₁ = v₁ / I

                                        = 2 V / 0.2 A

                                         = 10 Ω

Hence, the resistance of the  first resistor is, R₁ = 10 Ω