To produce a parallel beam of light from a concave mirror...
To produce a parallel beam of light from a concave mirror, the distance at a which the lamp should be placed from the mirror is equal to
the focal length
two times the focal length
the distance of the image
two times the radius of curvature
Correct answer is A
No explanation has been provided for this answer.
Which of the following statements about Archimedes' principle is correct? The upthrust on a body...
A 40W instrument has a resistance 90 Ohms. On what voltage should it be operated normally ...
In a discharge tube, most of the gas is pumped out so that electricity is conducted at? ...