What should a voltmeter that is attached to three batteries, each measuring 1.5 volts read:

The answer depends on the arrangement of the batteries either parallel or series.

If the three batteries are connected in parallel, the voltmeter will read the same voltage as the individual battery (I.e, the combine voltage will remain 1.5 Bolts)

While

If the batteries are connected in series, and are correctly connected together from positive to negative, the combine voltages will increase by adding individual battery voltage together. So for three 1.5 Volts batteries, the total voltages will be 4.5 Volts.

Explanation:

Parallel connected

Vp = 1.5 Volts

Series connection

Vs = 1.5 + 1.5 + 1.5 = 4.5Volts

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.

i really dont know but i will try okay.

so i think u would just add all them up and get your answer..