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
Exponential changes
Imagine an empty tube train (metro, if you prefer) pulling into a crowded station. When the doors open, people surge forward and the carriage starts to fill very quickly. As the number of people in the carriage increases, the number of remaining spaces decreases and the rate at which further people can board also decreases. … Continue reading Exponential changes
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)
How to Use Logarithms
Although they can seem confusing at first sight, logarithms are just mathematical functions that allow calculations to be carried out quicker than would otherwise be the case. So although they may seen daunting, you should think of logarithms as a way to make calculations easier – once you have mastered the rules. There is quite a … Continue reading How to Use Logarithms
