Mark and name the following on the outline map of the world with suitable index:
A canal bringing radical change in sea transport - Suez Canal.
Explain the construction of a spherical wavefront by using Huygens' principle.
The perpendicular distance of the plane \( r \cdot (3\hat{i} + 4\hat{j} + 12\hat{k}) = 78 \) from the origin is __________.
Derive an expression for maximum speed of a vehicle moving along a horizontal circular track.