Practical Questions

The diagram shows the scale on an analogue microammeter.

Which of the following is the correct reading?

• 28 × 10^-6 A

• 28 × 10^-3 A

• 36 × 10^-6 A

• 36 × 10^-3 A

In an experiment to measure viscosity of oil, ball bearings are dropped into a long measuring cylinder full of oil.

For one ball bearing, three measurements of its diameter are:

2.55 mm, 2.56 mm, 2.59 mm

Which of the following should be stated as the average result?

• 2.56 mm

• 2.566 mm

• 2.567 mm

• 2.57 mm

When conducting the experiment from question 2, which of the following would minimise parallax error when timing the ball bearing as it falls through a fixed distance in the oil?

• Ensure that the observer is at eye level with the ball bearing.

• Use a metre rule rather than the scale on the measuring cylinder.

• Use two parallel rubber bands around the measuring cylinder to indicate the fixed distance.

• Start and stop the clock as the middle of the ball bearing passes through the start and finish points.

In an experiment to measure the e.m.f. of a battery, a graph similar to the one in the diagram was drawn.

Which of the following gives the e.m.f. of the battery?

• area under the graph

• the gradient of the graph

• intercept with the current axis

• intercept with the potential difference axis

The picture below shows a multimeter similar to those used in many school laboratories.

The multimeter is used to measure the potential difference across the 100 Ohm resistor in the circuit. Which one of the following would be the best setting to use?

• 200 V

• 20 V

• 200 mV

• 2000 mV

In an experiment, an ammeter is used to measure the current in the 100 Ohm resistor in the diagram. Which one of the letters P, Q, R or S on the circuit diagram shows the best position for the ammeter?

• P

• Q

• R

• S

A student is investigating the variation in the emf generated by a solar cell with light intensity. She varies the distance between the solar cell and a lamp.

Which one of the following is the independent variable?

• distance

• emf

• light intensity

• power of the lamp

A student takes the following three measurements of the diameter in mm of a ball bearing.

4.21, 4.20, 4.21

Which one of the following should be stated as the average result?

• 4.2 mm

• 4.20 mm

• 4.207 mm

• 4.21 mm

A student is trying to determine his reaction time. He takes the following readings:

0.20 s, 0.18 s, 0.19 s, 0.08 s

Which of the following is the best mean value of his reaction time stated with a suitable uncertainty?

• 0.19 ± 0.06 s

• 0.19 ± 0.01 s

• 0.16 ± 0.06 s

• 0.16 ± 0.01 s

An experiment to determine the acceleration due to gravity uses a free-falling ball. Which of the following measurements would NOT be needed?

• initial velocity

• final velocity

• mass of the ball

• time taken