Which of the following instruments can detect the presence of a voltage, but not the voltage level?
a. clamp-type meter
b. wattmeter
c. multitester
d. neon circuit tester

A).  The clamp type meter tells you the current flowing through
the clamp, but not the voltage anywhere in the circuit.

B).  The wattmeter tells you the electrical power being poured
into it, but not the voltage anywhere in the circuit.

C).  The multitester has a little bit of everything.  When it's
set up properly, you can touch the tips of the meter's probes
anywhere you want to in the circuit, and it DOES display the
voltage between those two points.

D).  A neon circuit tester is a little neon light bulb that glows
orange when it's touched to a point in the circuit where the
voltage is above the ignition voltage of the neon, typically
something like 70 volts, I think.  But it can't tell you how MUCH
above that voltage.

So the ones that detect life but don't tell you the exact voltage
are  'A',  'B',  and  'D' .

The charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.