The above figure shows the variation of potential V or electric field with r for a point charge Q. Which of the given curves represent E versus r or V versus r ?

Question

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/d181587f57fb980a02550be4be1e8b69-.png" /> The above figure shows the variation of potential V or electric field with r for a point charge Q. Which of the given curves represent E versus r or V versus r ? (A) I arrow E versus r, II arrow V versus r (B) I arrow V versus r, II arrow V versus r (C) Both represent E versus r (D) None of the above

Tardigrade Admin · Accepted Answer

E=(K Q/r2) ⇒ E propto (1/r2) ⇒ V=(K Q/r) ⇒ V propto (1/r) So, for 0 < r < 1, the curve E will be above V and for r>1, the curve E will be below V at r=1, E=V

Q.
The above figure shows the variation of potential $V$ or electric field with $r$ for a point charge $Q$ . Which of the given curves represent $E$ versus $r$ or $V$ versus $r$ ?

$I \to E$ versus $r, II \to V$ versus $r$

$I \to V$ versus $r, II \to V$ versus $r$

Both represent $E$ versus $r$

None of the above

$E = \frac{K Q}{r ^{2}}$
$\Rightarrow E \propto \frac{1}{r ^{2}}$
$\Rightarrow V = \frac{K Q}{r}$
$\Rightarrow V \propto \frac{1}{r}$
So, for $0 < r < 1$ , the curve $E$ will be above $V$ and for $r > 1$ , the curve $E$ will be below $V$ at $r = 1, E = V$

Q. The above figure shows the variation of potential V or electric field with r for a point charge Q. Which of the given curves represent E versus r or V versus r ?

I→E versus r,II→V versus r

I→V versus r,II→V versus r

Both represent E versus r