Silver is best conductor with copper close behind.
best insulator depends on application. Teflon is best for very small currents, ceramic is probably best for high voltage, although a vacuum is also very good.
Answer:
The additional trials needed is 48 trials
Explanation:
Given;
initial number of trials, n = 16 trials
the standard deviation, σ = 0.24 s
initial standard error, ε = 0.06 s
The standard error is given by;

To reduce the standard error to 0.03 s, let the additional number of trials = x

Therefore, the additional trials needed is 48 trials.
Ohm’s Law states that electrical current is proportional to voltage and therefore inversely proportional to resistance - V = I x R