Time

Which of the following is NOT a unit of time?

• Second

• Year

• Interval

• Minute

Answer explanation

interval is a period of time and not a unit of time

Which of the following time device is used in the laboratory to measure time?

• Sand clock

• Stop clock

• Pendulum clock

• Wrist watch

Answer explanation

The Stop Clock is used mostly in fields and laboratories to determine time. It can measure time in fraction of seconds and minutes. In the laboratory, it is used to measure time intervals such as the period of oscillation in the pendulum experiment.

Which of the following is the best time device to determine if a task can be completed within a minute?

• Stop clock

• Pendulum clock

• Wrist watch

• Sand clock

Answer explanation

The Sand clock is an instrument designed to measure time per a given period interval. It is made of two glass bulbs joined together by a small neck. Sand is made to run from the top bulb to the bottom bulb through the neck. In most cases, the sand clock is used to check if an event can be completed within a particular time interval.

How many seconds are there in 2 days, 2 hours, and 35 minutes?

• 2235 seconds

• 3035 seconds

• 134100 seconds

• 182100 seconds

Answer explanation

((((2 x 24) + 2) x 60) + 35 ) x 60 = 182 100

A simple pendulum makes 50 oscillations in one minute. Determine its period of oscillation.

• 0.04 s

• 0.83 s

• 1.20 s

• 50.00 s

Answer explanation

Period = Elapsed time / number of oscillation

T = 60 / 50 = 1.2 s

A student found out from a simple pendulum experiment that 20 oscillations were completed in 38 seconds. What is the period of oscillation of the pendulum?

• 1.8 s

• 1.9 s

• 2.0 s

• 3.8 s

A boy timed 20 oscillations of a certain pendulum three times and obtained 44.3 s, 45.5 s, and 45.7 s respectively. Calculate the mean period of oscillation of the pendulum.

• 0.13 s

• 2.22 s

• 2.26 s

• 45.2 s