The value of critical angle for glass is_______________?
A point where the incident parallel rays of light converge or appear to diverge after passing through a lens is called______________?
Dioptre power of an concave lens of 10 cm focal length is_______________?
The minimum distance between an object and its real image in a convex lens is_____________?
A convex lens gives a virtual image only when the objects lies_________________?
Image of an object 5 mm high is only 1 cm high. Magnification produced by lens is__________________?
X-ray are________________?
Hydrogen atom does not emit X-rays because _________________?
Excited atoms return to their ground state in_______________?
In hydrogen spectrum which one of the following series lies in the ultraviolet region ?
