The equation θ = 1.22 λ/D was devised by_______________?

A. Newton
B. Einstein
C. Raleigh
D. Planks

Michelson calculated the speed of light using the instruments______________?

A. Spectrometer
B. Galvanometer
C. Interferometer
D. None of these

Ratio of the weight of H-atom to that of an electron is approximately______________?

A. 18.336
B. 1836
C. 18360
D. 183.6

In hydrogen spectrum which one of the following series lies in the ultraviolet region ?

A. Balmer series
B. Pfund series
C. Bracket series
D. Lymann series

Excited atoms return to their ground state in_______________?

A. 10-10s
B. 10-8s
C. 10-6s
D. 10-9s

Hydrogen atom does not emit X-rays because _________________?

A. Its energy levels are too close to each other
B. Its energy levels are too far apart
C. It is too small in size
D. It has a single electron

Two convex lenses of equal focal length f are placed in contact the resultant focal length of the combination is______________?

A. Zero
B. Focus
C. 2 f
D. F/2

Least distance of distinct vision_____________?

A. Increases with increase in age
B. Decreases with increase in age
C. Neither increases nor decreases
D. Becomes infinite after 60 years

Image of an object 5 mm high is only 1 cm high. Magnification produced by lens is__________________?

A. 0.5
B. 0.2
C. 1
D. 2

A convex lens gives a virtual image only when the objects lies_________________?

A. Between principal focus and center of curvature
B. Beyond 2 f
C. At the principal focus
D. Between principal focus and optical center