Question

The main plate of a transit is divided into 1080 equal divisions. 60 divisions of the vernier coincide exactly with 59 divisions of the main plate. The least count (in seconds) of the transit is

Answer 1

       The least count of transit is 20 seconds.

• Least count = length of one division on the main scale / number of divisions of vernier
• So, least count will be= s/n.
• The total degree of rotation in a plate=360°.
• So, S = 360/1080.
• N = 60 as given in question.  
• So the least count = 1/180 degrees = 20 seconds.

Answer 2

Answer:

20 seconds

Step-by-step explanation:

Least count = length of one division on the main scale/ no. of divisions of vernier.

Legth of one division on main scale= 360/1080.

= 0.3333333 degrees,

= 0.3333333 x 3600 sec,

= 1200 sec.

No of divisions of vernier = 60.

Therefore, Least count= 1200/60 = 20.