The bob of a simple pendulum takes 8.0s to complete 10 oscillations. Determine the frequency of oscillation of the bob.

Analyze the question: The bob completes 10 oscillations in 8.0 s. We need the frequency, which is the number of oscillations per second.

Concept: Frequency is the number of complete oscillations per unit time:

f = (number of oscillations) / (time taken)

Period is the time for one oscillation: T = t / n, and f = 1/T.

Solution:

Using the frequency formula directly:

f = 10 / 8.0 = 1.25 Hz

Check using the period:

T = 8.0 / 10 = 0.8 s f = 1/T = 1/0.8 = 1.25 Hz

Both methods agree.

Why the other options are wrong:

• A (0.125 Hz): this comes from dividing 1 by 8, ignoring the 10 oscillations.
• C (7.50 Hz): this is not obtained from any valid operation here.
• D (8.00 Hz): this is just the time, not the frequency.

Tip: Frequency is always "how many per second," so put the number of oscillations on top and the time on the bottom. Quick check: 10 oscillations in 8 s must be a little more than 1 per second, so about 1.25 Hz fits. Option A is far too small.