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How do you calculate the Flash-to-Bang?

User Jbryanh
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Final answer:

To calculate the necessary capacitor size in an RC circuit for a camera flash, use the equation T = RC, where T is the required flash duration and R is the resistance. For a bullet moving at 500 m/s and allowing 1 mm of motion blur, the required flash duration is 2 microseconds, from which the capacitance can be calculated.

Step-by-step explanation:

To calculate the size of the capacitor needed in an RC circuit for capturing a photo with a brief flash, we will use the relationship between the flash duration and the RC time constant, where T represents the time constant and is the product of resistance (R) and capacitance (C).

Given a bullet's speed of 500 m/s and assuming 1 mm of blur is acceptable, you can calculate the necessary flash duration by determining how long the bullet takes to travel this distance. The flash duration equals 1 mm / 500 m/s, or 2 μs (microseconds).

The RC time constant T should be equal to or less than the necessary flash duration for sharp imaging. Given that T = RC and the resistance of the flash tube is provided as 10 ohms, we can rearrange the formula to solve for C (C = T/R). Inserting the time constant T as 2 μs and the resistance value, the calculated capacitance would be 0.2 μF (microfarads).

In practice, this would help capture a clear image of the bullet moving through the object without motion blur, allowing for observations and measurements relevant to both scientific inquiry and potentially forensic analysis, similar to the technique used in the investigation of historical events such as the assassination of President John F. Kennedy in 1963.

User Aim
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