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Sensitivity, Meaning (SPM Physics)

The ability of an instrument to detect and respond to a small change in the quantity being measured.

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EnglishSensitivity
Bahasa MelayuKepekaan
中文灵敏度

Definition

The ability of an instrument to detect and respond to a small change in the quantity being measured.

Measurement

In exam terms

Sensitivity is the ability of an instrument to detect and respond to a small change in the quantity being measured. A sensitive instrument gives a large change in its reading for a small change in the quantity, so it can pick up fine differences.

For example, a liquid-in-glass thermometer is made more sensitive by using a thinner capillary bore and a larger, thinner-walled bulb, so a small rise in temperature moves the liquid a longer distance up the tube. A micrometer screw gauge (smallest division 0.01 mm) is more sensitive than a vernier caliper (0.1 mm).

Do not confuse it with accuracy

Do not confuse sensitivity with accuracy. Sensitivity is about detecting small changes; accuracy is about closeness to the true value.

A sensitive instrument is not automatically accurate, because it can still have a zero error.

In Paper 2 this appears as state one way to increase the sensitivity of the thermometer (answer: use a narrower capillary tube or a larger bulb), so read the command word carefully to give the change asked for, not a general improvement.

Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)

Frequently asked questions

How can a thermometer be made more sensitive?
Use a thinner (narrower) capillary bore and a larger, thinner-walled bulb, so a small temperature change moves the liquid a longer distance up the tube.
Is a micrometer more sensitive than a vernier caliper?
Yes. A micrometer screw gauge can read to 0.01 mm while a vernier caliper reads to 0.1 mm, so the micrometer detects smaller changes in length.
Does a sensitive instrument always give accurate readings?
No. Sensitivity only means it detects small changes. It can still have a zero error, which would make its readings inaccurate.

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