Question

Проводник включен в сеть с постоянным напряжением 120 В. Сила тока в проводнике при этом равна 1,5 А. Последовательно с проводником включили дополнительное сопротивление. Сила тока в цепи стала 1,2 А. Найти дополнительное сопротивление.

Answer 1

U=R1*I1
R1=U/I1
U=(R1+R2)*I2
R1+R2=U/I2
R2=(R1+R2)-R1=U/I2-U/I1=U(1/I2 - 1/I1)=120*(1/1,2-1/1,5)=20 Ом - это ответ

Answer 2

Calculation of Additional Resistance

To find the value of the additional resistance, we can use Ohm's Law, which states that the current flowing through a conductor is equal to the voltage across it divided by its resistance.

Given: - Voltage (V) = 120 V - Current (I) = 1.5 A (before adding the additional resistance) - Current (I') = 1.2 A (after adding the additional resistance)

We can calculate the resistance (R) of the conductor before adding the additional resistance using Ohm's Law:

R = V / I

Substituting the given values: R = 120 V / 1.5 A = 80 Ω

Now, let's calculate the resistance of the entire circuit after adding the additional resistance. Since the conductor and the additional resistance are connected in series, the total resistance (R_total) is the sum of the resistance of the conductor (R) and the additional resistance (R_add).

R_total = R + R_add

We know that the current in the circuit after adding the additional resistance is 1.2 A. Using Ohm's Law, we can calculate the total resistance:

R_total = V / I'

Substituting the given values: R_total = 120 V / 1.2 A = 100 Ω

To find the additional resistance (R_add), we can subtract the resistance of the conductor (R) from the total resistance (R_total):

R_add = R_total - R

Substituting the calculated values: R_add = 100 Ω - 80 Ω = 20 Ω

Therefore, the additional resistance in the circuit is 20 Ω.

Please note that the values used in this calculation are based on the information provided in the question. If there are any additional details or specifications, please let me know, and I'll be happy to assist you further.