1. **State the problem:** Rationalise the denominator of $\frac{\sqrt{7}}{\sqrt{3}}$ and simplify the expression. 2. **Formula and rule:** To rationalise a denominator containing a square root, multiply numerator and denominator by the conjugate or the same root to eliminate the root in the denominator. 3. **Apply the rule:** Multiply numerator and denominator by $\sqrt{3}$: $$\frac{\sqrt{7}}{\sqrt{3}} \times \frac{\sqrt{3}}{\sqrt{3}} = \frac{\sqrt{7} \times \sqrt{3}}{\sqrt{3} \times \sqrt{3}}$$ 4. **Simplify numerator and denominator:** $$\frac{\sqrt{21}}{3}$$ 5. **Final answer:** The expression with a rationalised denominator is $\frac{\sqrt{21}}{3}$, which is in its simplest form.