Electrical power of a lightbulb

In summary, the question asks for the ratio of electrical power between two light bulbs connected in series and in parallel. The formula for power is either ##P=I^2R## or ##P=\frac{V^2}{R}##. The total resistance in the first case is 2R and in the second case, it is R/2. Therefore, the ratio of power is 1/4.
  • #1
Firye Stanly
4
0

Homework Statement


Two identical light bulbs are connected to the ends of the battery. In the first case they are connected in series and in the second they are connected in parallel mode. What is the ratio of the electrical power of light bulbs connected as mentioned?

Homework Equations


##P=I^2R##
##P=\frac{V^2}{R}##

The Attempt at a Solution


Since the voltage is the same and i take a light bulb to be a resistor shouldn't it just be ##R_1/R_2##? It somehow should be 1/4 but i don't get how. Total resistance in the first case is ##2R## and in the second is ##2/R## right?
 
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  • #2
In the second case, total resistance is not 2/R. What is the formula for equivalent resistance of two parallel resistors?
 
  • #3
cnh1995 said:
In the second case, total resistance is not 2/R. What is the formula for equivalent resistance of two parallel resistors?
Parallel resistors ##1/R_t = 1/R+1/R## so its ##R/2## so its ##1/4## oh thanks!
 

1. What is the electrical power of a lightbulb?

The electrical power of a lightbulb refers to the amount of electrical energy it consumes per unit time. It is typically measured in watts (W) and is a measure of how bright the lightbulb will be.

2. How is the electrical power of a lightbulb calculated?

The electrical power of a lightbulb can be calculated by dividing the voltage (V) by the current (I) passing through the lightbulb. This is known as Ohm's Law, where power (P) equals voltage (V) multiplied by current (I): P = V x I.

3. Does the wattage of a lightbulb affect its brightness?

Yes, the wattage of a lightbulb directly affects its brightness. A higher wattage lightbulb will consume more electrical energy and produce a brighter light compared to a lower wattage lightbulb.

4. Can the electrical power of a lightbulb be changed?

Yes, the electrical power of a lightbulb can be changed by using a dimmer switch. This controls the amount of electrical energy flowing to the lightbulb, thus affecting its brightness.

5. How does the electrical power of a lightbulb impact its lifespan?

The higher the electrical power of a lightbulb, the shorter its lifespan will be. This is because a lightbulb that consumes more electrical energy will generate more heat, which can cause the filament to burn out faster.

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