Table of Contents
What is the relationship between current and voltage for a lightbulb?
The filament in an incandescent bulb does not have a constant resistance. If you take a bulb and increase the voltage across it, the current increases too. An increase in current means the bulb gets hot—hot enough to glow. As the temperature increases, however, the resistance also increases.
What is the relationship of voltage to current?
Ohm’s law defines the relationship between the voltage, current, and resistance in an electric circuit: i = v/r. The current is directly proportional to the voltage and inversely proportional to the resistance.
How does current affect lamp?
A filament lamp is a common type of light bulb. It contains a thin coil of wire called the filament. This heats up when an electric current passes through it, and produces light as a result. The resistance of a lamp increases as the temperature of its filament increases.
What equation would you use for current?
We can use the definition of current in the equation I = ΔQ/Δt to find the current in part (a), since charge and time are given.
What is the formula to calculate voltage?
voltage = current × resistance V = I × R
How do you find the resistance of a 240V lamp?
The resistance of an electrical component can be found by measuring the electric current flowing through it and the potential difference across it. This equation, called Ohm’s Law, shows the relationship between potential difference, current and resistance: 3 A flows through a 240 V lamp. What is the resistance of the lamp?
How do you find the voltage and resistance of a circuit?
voltage = current × resistance. V = I × R. where: V is the potential difference in volts, V. I is the current in amperes (amps), A. R is the resistance in ohms, Ω. The equation can be rearranged to find the resistance: R = V ÷ I.
What is the formula for OHM’s law?
Another way of representing Ohm’s Law was developed by Gustav Kirchhoff (of Kirchoff’s Laws fame), and takes the form of: J = σE. where these variables stand for: J represents the current density (or electrical current per unit area of cross section) of the material.