Step 1: Understanding Plate Boundaries.
A trench is typically formed at a convergent plate boundary, where two tectonic plates move toward each other, resulting in subduction.
Step 2: Analyzing the options.
(A) divergent plate boundary: Trenches do not form at divergent boundaries; these boundaries are characterized by the moving apart of tectonic plates.
(B) convergent plate boundary: Correct — Trenches are formed where one plate is subducted beneath another at a convergent boundary.
(C) transform boundary: Transform boundaries involve horizontal movement of plates and do not create trenches.
(D) passive margin: Passive margins are typically stable regions where no major tectonic activity, like trench formation, occurs.
Step 3: Conclusion.
The correct answer is (B) convergent plate boundary, where trenches are commonly found due to subduction zones.
Two boreholes A and B, both inclined towards 270°, penetrate a dipping coal bed at the same point and pass through it entirely in the sub-surface as shown in the figure below. The bed dips towards 270°. The thickness of the coal bed, measured along the borehole A is 10 m and along borehole B is 8 m. The angle between the two boreholes is 20°. The orthogonal thickness \( x \) of the coal bed is ........ m. (Round off to one decimal place) 
A well-developed succession of laminated shale is bound by two volcanic ash beds that were precisely dated as shown in the schematic diagram given below. Assuming a constant sedimentation rate, the age of the fossiliferous limestone bed 65 m above the basal volcanic ash bed is ............ Ma. (Round off to nearest integer) 
The data tabulated below are for flooding events in the last 400 years.
The probability of a large flood accompanied by a glacial lake outburst flood (GLOF) in 2025 is ........... \(\times 10^{-3}\). (Round off to one decimal place)
| Year | Flood Size | Magnitude rank |
|---|---|---|
| 1625 | Large | 2 |
| 1658 | Large + GLOF | 1 |
| 1692 | Small | 4 |
| 1704 | Large | 2 |
| 1767 | Large | 2 |
| 1806 | Small | 4 |
| 1872 | Large + GLOF | 1 |
| 1909 | Large | 2 |
| 1932 | Large | 2 |
| 1966 | Medium | 3 |
| 2023 | Large + GLOF | 1 |
A satellite launching vehicle is carrying a lander for Moon mapping.
As shown in the figure below, P is the position where the gravitational forces exerted by Earth and Moon on the vehicle balance out.
The distance \( P \) from the center of the Earth is ........... \(\times 10^5\) km. (Round off to two decimal places)
The isobaric temperature-composition (T–X) phase diagram given below shows the phase relation between components M and N. The equilibrium melting undergone by the rock R to generate the liquid of composition L is .............. % (In integer )