D43 MASTER THE DAY

Which part of the prismatic compass allows quick damping of needle oscillations?

• Agate cap
• Lifting lever
• Prism
• Breaking pin

Answer explanation

Breaking pin is used to bring the needle to rest quickly by reducing oscillations.

In surveyor’s compass, the bearing system used is:

• Whole Circle Bearing
• Reduced Bearing
• Azimuth Bearing
• Deflection Angle

Answer explanation

Surveyor’s compass uses the Quadrantal or Reduced Bearing (RB) system.

What is the function of the trough compass in plane table survey?

• To measure angles
• To center the instrument
• To level the board
• To orient the plane table to magnetic north

Answer explanation

Trough compass is used to orient the plane table using the magnetic north.

Which method in plane table surveying is suitable for inaccessible areas?

• Radiation
• Intersection
• Traversing
• Resection

Answer explanation

Intersection is ideal when distances cannot be measured or are inaccessible.

Which of the following errors is caused due to imperfect leveling in plane table survey?

• Instrumental error
• Observational error
• Plotting error
• Sighting error

Answer explanation

Poor leveling and bisection lead to observational or personal errors.

Which component of the alidade helps in drawing lines on the sheet?

• Vertical hair
• Ruling edge
• Level tube
• Graduated arc

Answer explanation

Ruling edge or fiducial edge is used for drawing lines on the plane table.

Which method in plane tabling is most accurate for orientation?

• Magnetic compass method
• Radiation
• Back sighting
• By estimation

Answer explanation

Back sighting is the most reliable and accurate method for orientation.

The plane table board is commonly made of which material?

• Plastic
• Mild Steel
• Seasoned wood
• Aluminum alloy

Answer explanation

The board is usually made of well-seasoned pine or teak wood.

Assertion (A): Magnetic declination is the angle between true and magnetic meridian. Reason (R): Magnetic bearing is measured from arbitrary meridian.

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

Answer explanation

R is false because magnetic bearing is measured from magnetic meridian, not arbitrary.

Assertion (A): Dip of needle is zero at the equator. Reason (R): At equator, magnetic lines are horizontal to Earth's surface.

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

Answer explanation

At equator, magnetic field lines are horizontal, hence dip is zero.