Question

Match List-I (Instrument) with List-II (Usage) and select the correct answer:

List-I:

A. Sextant

B. Tangent clinometer

C. Subtense bar

D. Heliotrope

List-II:

1. To determine the horizontal distance

2. To measure the angular distance

3. To establish right angles

4. To determine the difference in elevation between the points

5. To mark the positions of participants in a land survey

1. A - 2, B - 4, C - 1, D - 2
2. A - 4, B - 2, C - 1, D - 5
3. A - 2, B - 4, C - 1, D - 5
4. A - 2, B - 3, C - 4, D - 1

Answer 1

Correct Answer - Option 3 : A - 2, B - 4, C - 1, D - 5

Explanation

Sextant: 

• It is an instrument that is used to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation.
• The principle of a sextant is when the ray of light is reflected from two mirrors in succession in the same plane, then the angle between the incident and reflected ray is two times the angle between the mirrors

Clinometer:

• It is an instrument for measuring angles of slope, elevation, or depression of an object with respect to the ground. (Difference in elevation between points)
• A clinometer is a special case of a spirit level.
• While the spirit level is restricted to relatively small angles, clinometers can be used for much larger angles.
• These have an accuracy of one minute.
• Clinometers are used to determine the straightness and flatness of surfaces.

Subtense Bar:

• Subtense bar measures horizontal and vertical distance in places where chaining is impossible because of undulations and rough topography. But it can measure short distance up to 200 m.

Heliotrope:

• The heliotrope is an instrument that uses a mirror to reflect sunlight over great distances to mark the positions of participants in a land survey.