physics set 9

Q.13 An oil film floating on water surface exhibits colour pattern due to the phenomenon of:
A) Diffraction                             C)Interference
B) Polarization                           D) Surface tension
Q.14 The value of the least distance of distinct vision or near point is ______ for a normal human eye.
A) 20 cm                                   C) 10 cm
B) 25 cm                                   D) 15 cm
Q.15 In a compound microscope, the magnification by objective = 20, magnification by eyepiece = 11, then the total magnification is
A) M = -220                              C) M = -0.05
B) M = -0.19                              D) M = 220
Q.16 The distance between atoms is 0.30 nm. What will be the wavelength of X­rays at angle θ = 30o for 1st order diffraction?
A) λ = 0.60 nm                          C) λ = 0.20 nm
B) λ = 0.30 nm                          D) λ = 0.90 nm

Q.17 The value of least distance vision for normal eye is
A) 20 cm                                   C) 25 cm
B) 30 cm                                   D) 40 cm