17) E

You need to learn electricity equations which link power, current, voltage, energy and charge. Also, you need to learn the units of each measurement.

Let us look at the options:

**A**

joules/coulombs = Energy/Charge

We know the formula, Energy=Charge x Voltage

Hence, Voltage = Energy/Charge

**B**

amperes x ohms = Current x Resistance

We know V=IR which is Voltage = Current x Resistance

**C**

watts/amperes = Power/Current

We know P=VI which Power = Voltage x Current

Rearranging, we get Voltage = Power/Current

**D**

√watts x ohms = √Power x Resistance

We know:

P = VI and I = V/R

If we substitute I = V/R in P=VI, we get:

P=V²/R

V² = PR

V= √Power x Resistance

**E**

The given units cannot be used to manipulate equations.