Q1: Pick up the correct statement from the following :

ANS:D - all the above.

1. "It is difficult to eliminate an error completely at first trial." This statement acknowledges the fact that errors in surveying instruments or measurements may not be completely eliminated on the first attempt. Surveying involves various sources of error, including instrumental errors, environmental factors, and human errors. Achieving precise measurements often requires iterative adjustments and careful attention to detail.
2. "Instability of the instrument makes it almost impossible to adjust it satisfactorily." This statement highlights the challenge posed by instrument instability, which can make it difficult to achieve accurate and consistent measurements. Instrument instability can be caused by factors such as mechanical wear, environmental conditions (e.g., wind, temperature changes), or inadequate setup. Ensuring instrument stability is crucial for obtaining reliable survey data.
3. "Adjustment screws must be left bearing firmly but should never be forced." This statement emphasizes the importance of handling adjustment screws on surveying instruments with care. While adjustment screws are used to calibrate and fine-tune the instrument, they should be manipulated gently and precisely. Forcing adjustment screws can lead to damage or misalignment of the instrument components, resulting in inaccurate measurements.

Taken together, these statements underscore the complexity of surveying instruments and the challenges associated with achieving accurate and reliable measurements in the field. They highlight the importance of patience, attention to detail, and proper instrument maintenance and handling in surveying operations.