D45 QUIZ OF THE DAY

Assertion (A): Transition curves provide gradual change in curvature. Reason (R): They allow smooth introduction of super elevation.

• Both A and R are true, and R is the correct explanation of A
• Both A and R are true, but R is not the correct explanation of A
• A is true but R is false
• A is false but R is true

Answer explanation

Transition curves are provided to ensure smooth curvature and allow gradual super elevation; hence both A and R are true and R explains A.

Which of the following statements are true about a reverse curve? Statement I: Reverse curve connects two straights curving in same direction. Statement II: It consists of two arcs of opposite curvatures with common tangent.

• Only Statement I is correct
• Only Statement II is correct
• Both Statements I and II are correct
• Both Statements I and II are incorrect

Answer explanation

Only Statement II is correct. Reverse curves bend in opposite directions with a common tangent.

A simple circular curve has radius 300 m and deflection angle 60°. Find the length of curve.

• 314.16 m
• 150 m
• 173.2 m
• 282.74 m

Answer explanation

Length = (π × R × Δ) / 180 = (3.1416 × 300 × 60) / 180 = 314.16 m

For a simple circular curve of radius 300 m and deflection angle 60°, calculate the tangent length.

• 314.6 m
• 173.2 m
• 86.6 m
• 150.0 m

Answer explanation

Tangent Length = R × tan(Δ/2) = 300 × tan(30°) ≈ 300 × 0.577 = 173.2 m

Which method of curve setting uses two theodolites and requires no chaining?

• Rankine's Tangential Method
• Rankine's Two Theodolite Method
• Tacheometric Method
• Offset Method

Answer explanation

Rankine's Two Theodolite Method uses two theodolites and does not require chaining.

The ideal curve to be used in railway alignment is?

• Clothoid
• Cubic Parabola
• Lemniscate
• Reverse Curve

Answer explanation

Cubic Parabola is preferred for railways as it matches the super elevation requirement.

The point where two straights intersect and a curve begins is called?

• Point of Tangency
• Apex
• Point of Intersection
• Point of Curve

Answer explanation

Point of Curve is where the alignment changes from tangent to circular curve.

Which of the following is NOT an instrumental error in theodolite?

• Plate level axis not perpendicular
• Trunnion axis not perpendicular
• Incorrect bisection
• Eccentricity of plate

Answer explanation

Incorrect bisection is a personal error, not an instrumental error.

The axis of plate level should be ___ to the vertical axis.

• Perpendicular
• Parallel
• Inclined
• Curved

Answer explanation

Plate level axis must be perpendicular to vertical axis for proper leveling.

Which element is used to ensure exact centering in windy conditions?

• Optical plummet
• Plumb bob
• Tripod head
• Spirit level

Answer explanation

Optical plummet is used for stable centering when wind affects plumb bob.