A circular park of radius 20m is situated in a colony. Three boys Ankur, Syed and David are sitting at equal distance on its boundary each having a toy telephone in his hands to talk each other. Find the length of the string of each phone.

Three girls skatting on a circular ice ground of radius 200 m start from a point P on the edge of the ground and reach a point Q diametrically opposite to P following different paths as shown in Fig . 4.20 . What is the magnitude of the displacement vector for each ? for which girl is this equal to the actual length of path skate ?

An electric field is uniform and E=200 hatiNC^(-1) along +x s and E=-200hatiNC^(-1) along -x direction. A right circular cylinder of length 0.20 m and radius 0.05 m has its centre at the origin and its axis along the x-axis so that one face is x=+0.10m and the other =x-0.10m . a. What is the net outward flux through each flat face? b. What is the flux through the side of the cylinder? c. What is the net outward flux throught the cylinder? d. What is the net charge inside the cylinder?

Two chords AB and CD of length 5 cm and 11 cm respectively of a circle are parallel to each other and are on opposite sides of its centre. If the distance between AB and CD is 6 cm, find the radius of the circle.