An electron revolves in air in a circle in a plane perpendicular to the principal axis. The air has a uniform magnetic field parallel to the principal axis and of magnitude 2 tesla with centre of circle at a distance 10 cm from the pole of the spherical curved glass \[(\mu =1.5)\] surface of radius of curvature 10 cm as shown in figure. An observer from P sees radius of circle to be 10 mm. The linear momentum of electron is

• A. \[0.4\times {{10}^{-21}}kg-m/s\]
• B. \[0.8\times {{10}^{-21}}kg-m/s\]
• C. \[1.6\times {{10}^{-21}}kg-m/s\]
• D. \[2.4\times {{10}^{-21}}kg-m/s\]