A potentiometer is an accurate and versatile device to make electrical measurements of EMF because the method involves

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8^th bright fringe in the medium lies where 5^th dark fringe lies in air. The refractive index of the medium is nearly

A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle $$\theta $$, the spot of the light is found to move through a distance y on the scale. The angle $$\theta $$ is given by

A thin prism having refracting angle 10^o is made of glass of refractive infex 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination producess dispersion without deviation. The refracting angle of second prism should be