What is the voltage measured with a voltmeter across a wire in a circuit?

a) the voltage is the same as the voltage across the power source
b) the voltage is half of the voltage of the power source
c) the voltag is zero
d) a voltmeter cannot measure the voltage across a wire

Why do electron microscopes have higher resolving power than light microscopes?

Standing side by side ,you and a friend step off a bridge at different times and fall for 1.6s to the water below.your friend goes first,and you follow after he has dropped a distance of 2.0m.when your friend hits the water,is the seperation between the two of you 2.0m or more than 2.0m? verify your answer with a calculation.

Starting with only the balmer series light (visible light), how could we ensure that the solar panels generate a current that mark can use for his power station? a)by gradually increasing the brightness (amount) of light that we shine on it. b)by gradually increasing the frequency of the light we shine on it. c)by gradually increasing the wavelength of the light that we shine on it.