Variation of Apparent Brightness with Distance

It is reasonable to expect a lamp’s apparent brightness to decrease with increasing distance from the source but what is the best way to determine the nature of the variation? Although there’s a theoretical answer that applies to all electromagnetic waves, based on the inverse-square law, it is important to be able to carry out … Continue reading Variation of Apparent Brightness with Distance

Charging a Capacitor (analysis)

Changes in charge, current and potential difference during the charging and discharging of a capacitor are all exponential-type behaviours. Specifically, the current that transfers charge to or from a capacitor (during charging or discharging respectively) is always greatest at first and declines to zero as time increases. During discharging, the charge loss and the drop … Continue reading Charging a Capacitor (analysis)