Question

В сеть с напряжением 127 В включена электрическая лампа сопротивлением 240 Ом. Сопротивление подводящих проводов 14 Ом. Определить падение напряжения на лампе.

Answer 1

 на лампочке 120 В
на проводах 7 В

Answer 2

Calculating Voltage Drop Across the Lamp

To determine the voltage drop across the lamp, we can use Ohm's law, which states that the voltage drop (V) across a resistor is equal to the current (I) flowing through it multiplied by the resistance (R) of the resistor. The formula is:

V = I * R

Where: - V = Voltage drop across the resistor (in volts) - I = Current flowing through the resistor (in amperes) - R = Resistance of the resistor (in ohms)

In this case, the resistance of the lamp is 240 ohms and the resistance of the connecting wires is 14 ohms. The voltage across the circuit is 127 volts.

Calculating Current Flowing Through the Circuit

To calculate the current flowing through the circuit, we can use Ohm's law again. The total resistance in the circuit is the sum of the resistance of the lamp and the resistance of the wires.

Total Resistance (R_total) = Resistance of Lamp + Resistance of Wires

R_total = 240 ohms + 14 ohms

R_total = 254 ohms

Now, we can use Ohm's law to calculate the current flowing through the circuit:

I = V / R_total

Where: - I = Current flowing through the circuit (in amperes) - V = Voltage across the circuit (in volts) - R_total = Total resistance in the circuit (in ohms)

I = 127 V / 254 ohms

I = 0.5 A

Calculating Voltage Drop Across the Lamp

Now that we have the current flowing through the circuit, we can calculate the voltage drop across the lamp using Ohm's law:

V_lamp = I * R_lamp

Where: - V_lamp = Voltage drop across the lamp (in volts) - I = Current flowing through the circuit (in amperes) - R_lamp = Resistance of the lamp (in ohms)

V_lamp = 0.5 A * 240 ohms

V_lamp = 120 V

Therefore, the voltage drop across the lamp is 120 volts.