A real voltmeter has resistance Rv. In the circuit shown, thevoltmeter acts as a resistor, and affects the terminal voltage Vthat is mesures across the battery.
a) Derive an equation for V in terms of Rv, r, andε.
b) Say V is 1% less than the value of ε. Using the valuesr=0.75Ω and ε=4.5v, determine the voltmeter'sresistance.