Sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple. which of these tools should she use for this purpose? 1 an electronic balance 2 a stopwatch 3 a barometer 4 a graduated cylinder

Answer : The correct option is, (2) a stopwatch

Explanation :

Electronic balance : It is used to measure the amount of substance.

Stopwatch : It is used to measure the time.

Barometer : It is used to measure the pressure.

Graduated cylinder : It is used to measure the volume.

If sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple then the tool she use for this purpose is, a stopwatch.

Hence, the correct option is, (2) a stopwatch

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if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.