Answer:
The minimum value of the voltmeter resistance is 44.7 Ω
Explanation:
Given that,
Emf E= 7.50 V
Internal resistance r = 0.45 ohm
We need to calculate the voltmeter reading
[tex]V=(100-1)\%\ of\ E[/tex]
[tex]V=99\%\times V[/tex]
Put the value into the formula
[tex]V=0.99\times7.50[/tex]
[tex]V=7.425\ volt[/tex]
We need to calculate the current
Using formula of emf
[tex]E=V+ir[/tex]
[tex]ir=E-V[/tex]
[tex]i=\dfrac{E-V}{r}[/tex]
Put the value into the formula
[tex]i=\dfrac{7.50-7.425}{0.45}[/tex]
[tex]i=0.166\ A[/tex]
We need to calculate the minimum value of the voltmeter resistance
Using ohm's law
[tex]V=iR[/tex]
[tex]R=\dfrac{V}{i}[/tex]
Put the value into the formula
[tex]R=\dfrac{7.425}{0.166}[/tex]
[tex]R=44.7\ \Omega[/tex]
Hence, The minimum value of the voltmeter resistance is 44.7 Ω
