An object placed at infinity in front of a convex mirror forms image at MCQ with Answer and Explanation

Explanation:
Least count determines precision: two decimal places. So 2.50 cm. Extra digits indicate false precision.

Explanation:
Power negative means concave lens. f = 1/P (in metre) = 1/(-2.5) = -0.4 m = -40 cm. So concave lens of focal length 40 cm. Focal length negative for concave.

Explanation:
According to Gauss's Law in electrostatics, all excess charge on a conducting body resides entirely on its outer surface. Since there is no net charge enclosed within the hollow interior, the electric flux and consequently the electric field everywhere inside the hollow conducting sphere is exactly zero.