82. Which physical quantity has unit of pascal - second ?
83. Which physical quantity has unit of joule - second ?
86. For measurement of astronomical distance ________ is used.
87. Which microscope is used to measure the dimension of particle having dimension less than
A. electron microscope
B. simple microscope
C. optical microscope
D. none of above
Answer : Option A
88. In electron microscope electron behave like ________
89. Which wave length of light is used in an optical microscope ?
90. The intercepted area of the spherical surface about the center is