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Assume that an electric field $$\vec{E} = 30x^2\hat{i}$$ exists in space. Then the potential difference $$V_A - V_O$$, where $$V_O$$ is the potential at the origin and $$V_A$$ the potential at x = 2 m is:
We start with the fundamental electrostatic relation that connects the electric field to the electric potential:
$$\vec{E} = -\,\nabla V$$
Along the x-axis only, this gradient reduces to a simple derivative, so the x-component of the field satisfies
$$E_x = -\,\frac{dV}{dx}.$$
The problem gives the field as $$\vec{E} = 30x^2\,\hat i,$$ which means
$$E_x = 30x^2.$$
Equating the two expressions for $$E_x$$ we have
$$30x^2 = -\,\frac{dV}{dx}.$$
Now we isolate $$dV$$:
$$\frac{dV}{dx} = -30x^2 \quad\Longrightarrow\quad dV = -30x^2\,dx.$$
To obtain the potential difference between the point $$A$$ at $$x = 2\ \text{m}$$ and the origin $$O$$ at $$x = 0\ \text{m},$$ we integrate $$dV$$ from 0 to 2:
$$V_A - V_O \;=\; \int_{x=0}^{x=2} dV \;=\; \int_{0}^{2} \left(-30x^2\right)dx.$$
We compute the integral step by step:
First, integrate $$x^2$$:
$$\int x^2\,dx = \frac{x^3}{3}.$$
Now include the constant $$-30$$ and apply the limits:
$$V_A - V_O = -30 \left[ \frac{x^3}{3} \right]_{0}^{2}.$$
Simplify the coefficient:
$$-30 \times \frac{1}{3} = -10,$$
so
$$V_A - V_O = -10 \left[x^3\right]_{0}^{2}.$$
Evaluate at the upper and lower limits:
At $$x = 2,$$ $$x^3 = 2^3 = 8.$$
At $$x = 0,$$ $$x^3 = 0^3 = 0.$$
So
$$V_A - V_O = -10 \left(8 - 0\right) = -10 \times 8 = -80.$$
The SI unit of potential difference is volt, equivalent to $$\text{J C}^{-1}.$$ Thus
$$V_A - V_O = -80\ \text{J C}^{-1}.$$
The negative sign indicates that point $$A$$ is at a lower potential than the origin.
Hence, the correct answer is Option C.
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