Unit 1 Things to master

Question 1

Describe what the digital calipers is used to do.

Answer 1

The digital calipers are used to measure the internal and external diameters of an object accurately. The object is gripped gently using the jaws of the caliper and the diameter of the object is shown on the digital display. The depth bar can be used to measure the depth of an object.

Question 2

What are the steps to measure the dimension of the object by using a digital calipers?

Answer 2

• close the jaws of the calipers with no object in between
• press the origin button and reopen the jaws.
• the object is placed between the external or internal jaws of the calipers depending on the type of measurement.

Question 3

What are the steps to measure the dimension of the object by using digital micrometer screw gauge?

Answer 3

• Turn the ratchet until the spindle is in contact with the anvil with no object in between
• press the rezero button and reopen the spindle.
• the object is placed between anvil and spindle.
• the ratchet is turned until clicks are heard
• this indicates that the hold is now of the correct pressure and any further movement of the spindle will compress the object.

Question 4

What is the example of usage of measuring tape?

Answer 4

Height of a room

Question 5

What is the example of usage of metre ruler?

Answer 5

Height of a table

Question 6

What is the example of usage of analogue vernier calipers?

Answer 6

Diameter of a test tube

Question 7

What is an example of usage of analogue micrometer screw gauge?

Answer 7

Diameter of a wire

Question 8

What is an example of usage of digital calipers?

Answer 8

Diameter of a test tube

Question 9

What is an example of usage of digital micrometer screw gauge?

Answer 9

Diameter of a wire

Question 10

What are some examples of systematic errors?

Answer 10

• not accounting for zero error in a measurement. An instrument has a zero error if the scale reading is non-zero before a reading is taken. Instruments should be checked for zero error and the zero error must be accounted for in the measurement.
• not accounting for background radiation when measuring activity of a radioactive source.

Question 11

Is it true that errors has nothing to do with accuracy and precision?

Answer 11

Yes, yes that is true.

Question 12

What is the definition of random errors?

Answer 12

Random errors result in readings or measurements being scattered around a mean value. These errors have equal chance of being positive or negative.

Question 13

How can random errors be reduced?

Answer 13

• repeating a measurement and averaging
• plotting a graph and drawing a line of best fit for the plotted points

Question 14

What are some examples of random errors?

Answer 14

• fluctuation in the count-rate of a radioactive decay
• variation in the diameter of a piece of wire

Question 15

What is/are the error(s) can be eliminated?

Answer 15

systematic error

Question 16

By doing what will allow a systematic error to be eliminated? On the other hand, doing what will not allow systematic error to be eliminated?

Answer 16

A systematic error can be eliminated only if the source of the error is known and accounted for. It cannot be eliminated by repeating measurements and averaging them.

Question 17

What is the definition of systematic errors?

Answer 17

Systematic errors results in all readings or measurements being always above or always below the true value by a fixed amount.

Question 18

What is the formula for deriving the period of a pendulum?

Answer 18

T = 2 pi (square root of L/g)

Where L is the length of the pendulum
And g is 9.81m/s square