# Finding electrical energy used by a light

• owtu
In summary, the problem asks to find the electrical energy used by a light with a voltage of 110 V and a current of 10 mA in 2.0 minutes. The formula used is P = I * V, and the result is converted to Joules by multiplying by 120 seconds. The correct formula to use is one that links the given values of voltage, current, time, and energy. The SI unit for energy is the Joule and the unit for resistance is the Ohm.
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## Homework Statement

find electrical energy used by the light if the voltage on the battery is 110 V and the current in 2.0 minutes is 10 mA

V = 110
I = 10 mA

R = V/I

## The Attempt at a Solution

110 V /.010 A

= 11,000 ohms

= 11 k ohms

I'm new to this, did I do this problem right?

The SI unit of energy is the Joule. The Ohm is the unit of resistance.

Which is the correct formula that I should be using?

Think of a formula that links all the givens, that is, voltage, current, time and energy.

Might be easier to find two formula?

One that gives you the power from some of the givens.
One that gives you energy from power and another given.

I think I found it

P = I * V

then I multiply power, in watts, by 2 minutes and I got an answer in Joules, is that it?

Note the SI unit for time..

multiply by 120 seconds

Job done :thumbs:

1 person

## 1. How does a light produce electrical energy?

A light produces electrical energy through a process called electromechanical conversion, where a magnetic field is used to convert mechanical energy into electrical energy. In simple terms, the movement of electrons within the light's circuit creates an electric current, which powers the light.

## 2. What factors affect the amount of electrical energy used by a light?

The amount of electrical energy used by a light can be affected by several factors, including the wattage of the light bulb, the efficiency of the light fixture, and the length of time the light is turned on. The type of light bulb used, such as LED or incandescent, can also impact the amount of energy consumed.

## 3. How can I calculate the electrical energy used by a light?

To calculate the electrical energy used by a light, you will need to know the wattage of the light bulb and the length of time the light is turned on. You can then use the formula E = P x t, where E is the energy used in watt-hours, P is the power of the light bulb in watts, and t is the time in hours.

## 4. Can a light use too much electrical energy?

Yes, a light can use too much electrical energy if it is left on for extended periods of time or if a higher wattage bulb is used than necessary. Using energy-efficient light bulbs and turning off lights when not in use can help reduce the amount of electrical energy used.

## 5. How can I decrease the amount of electrical energy used by a light?

To decrease the amount of electrical energy used by a light, you can switch to energy-efficient light bulbs, such as LEDs, and make sure to turn off lights when they are not needed. You can also use dimmer switches to control the amount of light and energy used. Proper maintenance, such as cleaning and replacing filters and bulbs, can also help improve efficiency and reduce energy consumption.

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