A lamp source has a voltage of 110 volts and a current of 0.9 amperes. What is the resistance of the lamp?

A lamp source has a voltage of 110 volts and a current of 0.9 amperes. What is the resistance of the lamp?

• A. 110 ohms
• B. 98 ohms
• C. 135 ohms
• D. 122.2 ohms

Answer: (D)

Resistance is found by dividing the voltage across an element by the current through it. For this lamp, R = V / I = 110 V / 0.9 A = 122.222... ohms, which rounds to 122.2 ohms. This is the correct value because it directly applies Ohm’s law (resistance = voltage divided by current). Multiplying voltage by current would give power, not resistance, so that path wouldn’t yield the right result.

Resistance is found by dividing the voltage across an element by the current through it. For this lamp, R = V / I = 110 V / 0.9 A = 122.222... ohms, which rounds to 122.2 ohms. This is the correct value because it directly applies Ohm’s law (resistance = voltage divided by current). Multiplying voltage by current would give power, not resistance, so that path wouldn’t yield the right result.