A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1 cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is × 10-6 m.

Question

A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1 cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is × 10-6 m. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

50 VSD =49 MSD 1 VSD =(49/50) MSD Least count =1 MSD -1 VSD =(1-(49/50)) MSD =(1/50) MSD 1 MSD =(1/40) cm Least count =(1/50 × 40) cm =(1/2000) cm =(1/2) × 10-5 m =0.5 × 10-5 m =5 × 10-6 m

Q. A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is _____×10−6m.

50VSD=49MSD 1VSD=5049​MSD Least count =1MSD−1VSD =(1−5049​)MSD=501​MSD 1MSD=401​cm Least count =50×401​cm =20001​cm=21​×10−5m =0.5×10−5m =5×10−6m

Q. A travelling microscope is used to determine the refractive index of a glass slab. If $40$ divisions are there in $1 c m$ on main scale and $50$ Vernier scale divisions are equal to $49$ main scale divisions, then least count of the travelling microscope is _____ $\times 1 0^{- 6} m$ .