A 16 cd lamp is placed at a distance of 2 m from a 4 cd lamp. Find the position of the point at which the two lamps produce the same illumination.

Find the distance of the point (2,3,4) from the x axis.

A lens placed at a distance of 20 cm from an object produces a virtual image 2//3 the size of the object. Find the position of the image, kind of the lens and its focal length.

Two point charges of +16muC and -9muC are placed 8 cm apart in air. Determine the position of the point at which the resultant electric field is zero.

A concave mirror has a focal length of 20 cm and an object is placed at a distance of 16 cm from it.Find the position of the image formed by it.

An object is placed at a distance of 1.5 m from a screen and a convex lens is interosed between them .the magnification produced is 4.What is the focal length of the lens?

An object 2 cm high is placed at a distance of 5 cm from a concave mirror,whose radius of curvature is 20 cm.Find the position of the image.

Find the distance of (-1,2,5) from the plane passing through the point (3,4,5) whose direction ratios are .

Two point charges of - 16 muC and + 80 muC are placed 8 cm apart. Find the position of the point, where electric field is zero.