Question

the radius ofcarvature of concave miroor is 30cm where should an object placed from the mirror so as to form its image at infinity ?draw a diagramto justify your answer.... plzz give me fast its urgent

Answer 1

for the image to be at infinity,the object should be at principal focus of concave mirror.

thus,object should be placed at a distance of 15cm from the mirror.

Answer 2

C=-30 cm 
to form an image at infinity,the object should b plaed at focus.i.e.at 15 cm away from the mirror.