MCQ
Which is the correct expression for half-life
- A${(t)_{1/2}} = \log \,2$
- B${(t)_{1/2}} = \frac{\lambda }{{\log \,2}}$
- C${(t)_{1/2}} = \frac{\lambda }{{\log \,{\rm{2}}}}(\,2.303)$
- ✓${(t)_{1/2}} = \frac{{2.303\,{\rm{ log\,2}}}}{\lambda }$
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Assertion $A :$ For a simple microscope, the angular size of the object equals the angular size of the image.
Reason $R$ : Magnification is achieved as the small object can be kept much closer to the eye than $25\, cm$ and hence it subtends a large angle.
In the light of the above statements, choose the most appropriate answer from the options given below: