Exams › JEE Main › Physics
In an experiment the angles are required to be measured using an instrument, 29 divisions of the main scale coincide with 30 divisions of the vernier scale. If the smallest division of the main scale is half-a-degree ( = 0.5°), then the least count of the instrument is:
- half minute
- one degree
- half degree
- one minute
Correct answer: one minute
Solution
The least count of the instrument is determined by the formula: Least Count = Value of one main scale division - Value of one vernier scale division. Since 29 divisions of the main scale coincide with 30 divisions of the vernier scale, the value of one vernier scale division is smaller than one main scale division, leading to a least count of one minute.
Related JEE Main Physics questions
- A body has a measured mass of 5.00 ± 0.05 kg and a measured volume of 1.00 ± 0.05 m³. What is the maximum possible percentage error in its density?
- A substance has a density of 4 g/cm³ in the CGS system. If a new unit system is used where the unit of length is 10 cm and the unit of mass is 100 g, what is the numerical value of the density in that system?
- Which of the following physical quantities has dimensions that do not match the other three?
- If the percentage uncertainties in measuring mass M, length L, and time T are 1%, 1.5%, and 3% respectively, what is the percentage error in a quantity having dimensions M L⁻¹ T⁻¹?
- If E, m, J and G denote energy, mass, angular momentum and the gravitational constant, respectively, then the dimensional formula of EJ²/(m⁵G²) is identical to that of which quantity?
- A rod was found to have a measured length of 3.50 cm. Which measuring device was used for this reading?
⚔️ Practice JEE Main Physics free + battle 1v1 →