Answered

When the flash unit is used, there is a mean potential difference of [tex][tex]$200 V$[/tex][/tex] across the fluorescent tube. The flash of light lasts for [tex]2.8 \times 10^{-4} s[/tex], and 1.4 [tex][tex]$J$[/tex][/tex] of energy is transferred.

Calculate the mean current.
Use the Physics Equations Sheet.



Answer :

To find the mean current in the given setup, we need to follow a series of steps using the relevant physics equations. Let's break it down:

Firstly, we are given:
- Potential difference (V) = 200 volts (V)
- Time (t) = [tex]\(2.8 \times 10^{-4}\)[/tex] seconds (s)
- Energy (E) = 1.4 joules (J)

1. Finding the charge moved, [tex]\(Q\)[/tex]:

The relationship between energy (E), potential difference (V), and charge (Q) is given by the equation:
[tex]\[ E = V \times Q \][/tex]
Rearrange to solve for [tex]\(Q\)[/tex]:
[tex]\[ Q = \frac{E}{V} \][/tex]

Plugging in the given values:
[tex]\[ Q = \frac{1.4 \text{ J}}{200 \text{ V}} \][/tex]

[tex]\[ Q = 0.007 \text{ coulombs (C)} \][/tex]

2. Finding the mean current, [tex]\(I\)[/tex]:

Current (I) is the rate of flow of charge and is defined by the equation:
[tex]\[ I = \frac{Q}{t} \][/tex]

Using the charge [tex]\(Q\)[/tex] we found earlier and the given time [tex]\(t\)[/tex]:
[tex]\[ I = \frac{0.007 \text{ C}}{2.8 \times 10^{-4} \text{ s}} \][/tex]

[tex]\[ I = 25 \text{ amperes (A)} \][/tex]

Therefore, the mean current when the flash unit is used is [tex]\(25 \text{ A}\)[/tex].