What is the flash wattage for a camera flash with a 765 µF capacitor at 345 V?

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In summary, the electronic flash attachment for a camera uses a capacitor with a potential difference of 345 V and capacitance of 765 µF to produce a flash. The energy used to produce the flash is 45.527 J. To find the wattage of the flash, the energy difference on the capacitor before and after the flash must be divided by the time of the flash.
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StudentofPhysics
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The electronic flash attachment for a camera contains a capacitor for storing the energy used to produce the flash. In one such unit, the potential difference between the plates of a 765 µF capacitor is 345 V.

(a) Determine the energy that is used to produce the flash in this unit.

Using the formula:
Energy = .5C(V^2) i found the energy to be 45.527 J

(b) Assuming that the flash lasts for 5.0 10-3 s, find the effective power or "wattage" of the flash.


I can not find a formula to convert the given information into wattage however.
 
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  • #2
i'd calculate the energy difference on the capacitor (before and after the flash) and divide it by the time of the flash...
 
  • #3
The defenition of power is the change in energy per unit time. Can you do the problem now?
 
  • #4
how do i know what the energy is before and after the flash? Would it be that energy before then 0 after?
 
  • #5
ok, i undersstand know. I take the energy I found and simply divide it by the time passed. Thank you.
 

1. How do I convert watts to other units?

To convert watts to other units, you can use the formula: 1 watt = 1 joule/second. Therefore, to convert watts to joules, you can simply multiply the watt value by the number of seconds. To convert watts to kilowatts, divide the watt value by 1000. To convert watts to horsepower, multiply the watt value by 0.00134.

2. Is watt a unit of energy or power?

Watt is a unit of power, which is the rate at which energy is generated or consumed. It is the amount of energy transferred per unit time. Energy, on the other hand, is measured in joules, which is the amount of work done by a force of one newton over a distance of one meter.

3. Can watts be negative?

Yes, watts can be negative. Negative watts indicate that the energy is being consumed or used, rather than generated. This is common in electrical circuits where power is flowing in the opposite direction.

4. How do I calculate watts from voltage and current?

To calculate watts from voltage and current, you can use the formula: Watts = Volts x Amps. This is known as Ohm's law and is commonly used in electrical calculations. For example, if you have a circuit with a voltage of 12 volts and a current of 2 amps, the wattage would be 24 watts (12 x 2 = 24).

5. Can watts be converted to other energy units like calories or BTUs?

Yes, watts can be converted to other energy units such as calories or BTUs. However, these conversions are not as straightforward as converting to joules, kilowatts, or horsepower. You would need to know the specific conversion factor for each unit. For example, 1 watt is equivalent to 0.2388459 calories per second and 1 watt is equivalent to 0.000947817 BTUs per second.

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